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SCIENTIFIC AMERICAN SUPPLEMENT NO. 1082
NEW YORK, SEPTEMBER 26, 1896.
Scientific American, established 1845.
Scientific American Supplement. Vol. XLII., No. 1082.
Scientific American Supplement, $5 a year.
Scientific American and Supplement, $7 a year.
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TABLE OF CONTENTS.
PAGE I. ARCHITECTURE.—New Methods of Building Construction at Paris.—A typical French system of construction.—Combination of plaster and iron; cement arm.—1 illustration. 17292
II. AUTOCARS.—The De Dion and Bouton Road Motor.—An elaborate description of this typical French motor operated by steam.—4 illustrations. 17290
III. CHEMISTRY.—An Air Bath.—By B.J.H. COSTE.—1 illustration. 17296
The Feculometer.—1 illustration. 17295
IV. DOMESTIC ECONOMY.—Errors in Our Food Economy.—A very practical paper on scientific nutrition. 17288
V. GEOGRAPHY.—Zanzibar.—An account of the country and the recent events there.—3 illustrations. 17287
VI. MATHEMATICS.—Goodman's Hatchet Planimeters.—Instrument for measuring areas and mean altitudes or irregular figures.—5 illustrations. 17293
VII. METALLURGY.—The Great Krupp Works.—Notes on the great iron and steel works of the German empire, with statistics. 17302
VIII. MINERALOGY.—Precious Stoned—By Prof. HENRY A. MIERS.—Lecture I.—First installment of a most interesting article on the minerals used in the jeweler's art.—3 illustrations. 17298
IX. MINING ENGINEERING.—Firedamp Testing Station at Marchienne-au-Pont.—An elaborate experimental station for investigation into firedamp.—3 illustrations. 17297
X. MISCELLANEOUS.—Device for the Display of Lantern Slides.—An apparatus for the display of lantern slides in the shop window.—A rotating carrier.—2 illustrations. 17295
What the Sea Has Taken.—Destruction of great areas of country in the past, with special reference to the Dutch coast. 17289
Engineering Notes. 17301
Electrical Notes. 17301
Miscellaneous Notes. 17301
Selected Formul. 17302
XI. NATURAL HISTORY.—Some Notes on Spiders.—By Rev. SAMUEL BARBER.—Some very curious observations on arachnids. 17300
XII. NAVIGATION.—From New York to Havre in a Rowboat.—The most wonderful trip on record across the ocean, with portraits of the navigators and view of the boat.—2 illustrations. 17291
The Waste of Shipping:—Losses of steam and sailing vessels due to wreckage and condemnation, with valuable tables. 17291
XIII. OPTICS.—The Colors Named in Literature.—With table. 17289
XIV. PHOTOGRAPHY.—Photography for Chemists.—Lantern slides by reduction.—How to produce lantern slides from large negatives. 17297
XV. PHYSICS.—A Research on the Liquefaction of Helium.—A research in advanced experimental physics upon the newly discovered element helium.—1 illustration. 17299
Physics Without Apparatus.—Several interesting and simple experiments described.—1 illustration. 17302
XVI. TECHNOLOGY.—Apparatus for the Manufacture of Acetylene Gas.—Description of a number of prominent acetylene apparatus, with illustrations and sectional views thereof.—12 illustrations. 17294
Belleek China.—History of this beautiful china, and foundation of its manufacture in Ireland and subsequent introduction into America.—Description of different Belleek marks. 17292
The Coming Light.—An incandescent gas burner employing artificial draught produced by electric motor.—2 illustrations. 17296
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ZANZIBAR.
The sudden death on August 25 of Sultan Hamid bin Thwain, the ruler of Zanzibar, the attempted usurpation by Seyyid Khalid, and the bombardment of the palace by the British warships, have directed public attention to this comparatively little known but important city on the east coast of Africa.
The Zanzibar dominions achieved their independence some forty years ago under Seyyid Majid, whose father was Seyyid Said, the Sultan of Muscat and Zanzibar. The dominions formerly extended from Warsheik south to Tanghi Bay. In 1890 the coast line from Ruvuma to Wanga, with the island of Mafia, was ceded to Germany, by which partition the country was reduced to two islands, Zanzibar and Pemba, containing about a thousand square miles with 165,000 inhabitants, a strip of coast line ten miles long, together with three smaller islands and five seaports. Zanzibar is a British protectorate, as are also the Zanzibar dominions on the mainland as far north as the mouth of the Juba. The remainder of the mainland dominions to the south are leased to an Italian company.
The island of Zanzibar, together with the neighboring islands of Pemba and Mafia, to the north and south, is generally of coral formation, with here and there hills of a reddish clay, which rise in the south to an elevation of 450 feet and in the north develop into a range of hills which runs parallel to the shore at a height of over 1,000 feet. The dense forests which originally covered the island have been cut down, and the soil, which is of unusual fertility, is under thorough cultivation, yielding heavy crops of corn and manioc, which latter forms the staple food of the people.
The soil and climate are specially suited to the clove, which is raised in great quantities, the crop forming four-fifths of the total clove crop of the world. The seaboard lying opposite the island of Zanzibar is level and swampy, and the many rivers which flow from the escarpment of the great inland plateau have brought down a vast deposit of rich alluvial matter, upon which, aided by the moist, warm climate, a dense growth of tropical vegetation flourishes. A native growth of this region is the copal tree, famous as yielding the best gum known to commerce. Rice, maize, millet, the cocoa nut and the oil palm are cultivated, and the whole country is well adapted to the raising of sugar, coffee, cotton, indigo, and the various spices.
Of the original races of the island of Zanzibar only a few representatives survive. These live on the east side, and are known as Wa-Hadimu Bantus. The main population is a strange mixture of "full blood and half-caste Arabs, Indian 'Canarians' (that is, half-caste Portuguese from Kanara on the Malabar coast of India), Swahili of every shade, slaves or freedmen from all parts of East Africa," with a small sprinkling of Americans and Europeans.
The city of Zanzibar is, next to Alexandria and Tunis, the largest city on the coast of Africa, and contains a population variously estimated at from 80,000 to 100,000 souls. It is easily separable into two quarters, the trading quarter, which lies along the beach and contains the palace of the Sultan, and the eastern outlying suburb in which live the lower class. The view of Zanzibar from the sea is picturesque, the palace, forts and towers, the Mission Cathedral and the successive white buildings of varied outline, making a pleasing panorama. But when the visitor passes into the heart of the city he loses himself in a tangle of foul and narrow streets, where filth and immorality abound.
The palace, which is the central point of the city's life, is thus described by a former resident, Mr. Charles L. Lyons: "A low, rambling structure divided into three parts. The higher portion is of stone, and surrounded by verandas of carved teak wood, which are very ornate and elaborate specimens of eastern decorative art work. Adjoining this is the section occupied as living apartments, and the third section is occupied by the harem, which, under the late Sultan, comprised about twenty-five Circassian women.
"The palace was a curious combination of magnificence and tawdriness. The reception room, which is about 250 ft. square, was hung with beautiful draperies embroidered in real gold. In many places the walls were inlaid with precious stones curiously and indiscriminately mingled. Next to a valuable uncut sapphire or a ruby one would find a carbuncle or some valueless stone. Many of the chairs in the finer apartments were of gold inlaid with precious stones, and about many of the rooms were inscriptions from the Koran applied in solid gold." Other conspicuous buildings as seen from the water are the Government House, the Custom House, the Signal Tower, and the Mission Cathedral.
The harbor affords a fine anchorage for shipping, and is well worthy to be the central shipping point of the east coast of Africa. The total imports for 1894 were valued at over $6,000,000 and the exports at about $5,500,000. British India controls the greater share of the import trade, sending over large cargoes of grain, rice, and piece goods from Bombay, the yearly value of the trade being $1,675,000. The German trade amounts to $340,000, and a large amount of cotton goods and kerosene oil is imported from America.
The law of succession to the throne of Zanzibar does not recognize the right of the eldest son or the son of the eldest brother deceased. In the eyes of the Mohammedan Council of State Seyyid Khalid, the late usurper, has no stronger claim to the throne than his cousin, the present Sultan Hamid bin Mohammed bin Seyyid. Khalid is spoken of as "a rash and willful young man of twenty-five," and Hamid as "an elderly gentleman, fifty or sixty years of age, respected for his prudent and peaceable conduct, acceptable to the better class of Mussulman townsfolk, and trusted as a ruler likely to preserve the traditional policy of the realm." Immediately upon the interment of the late Sultan, however, which took place two short hours after his suspicious death, Khalid proclaimed himself ruler. He gathered the palace guards together, placed barricades in the palace square, trained the guns upon the British warships, and awaited developments. They came the next morning in the shape of an ultimatum from Admiral Rawson of the St. George, a first class cruiser of 7,700 tons, which, together with four smaller cruisers and gunboats, lay off the city in the harbor, summoning Khalid to surrender, leave the palace, and make his soldiers pile their arms in front of it. If he failed to do this, the palace would be bombarded within two hours after the dispatch of the ultimatum.
As Khalid's reply was to further strengthen his defense, at the appointed time the bombardment began. Meanwhile the loyal Zanzibar troops, with a detachment of British marines and seamen, attacked the barricades. The palace was knocked to pieces and set on fire by the shells, and Khalid, driven from the shelter, fled to the German consulate for safety.
Hamid was proclaimed Sultan by General Matthews, Mr. Cave, the consul, and Admiral Rawson, and order was at once restored to the city.
At the time of the bombardment it was freely predicted that the annexation of Zanzibar would speedily follow; but it now appears that the government considers that no advantages are to be gained by such a step, the cost of a direct administration being much greater than the native administration, which under the present protectorate is working satisfactorily.
We are indebted for our illustrations to the Illustrated London News and to Black and White.
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ERRORS IN OUR FOOD ECONOMY.
Scientific research, interpreting the observations of practical life, implies that several errors are common in the use of food.
First, many people purchase needlessly expensive kinds of food, doing this under the false impression that there is some peculiar virtue in the costlier materials, and that economy in our diet is somehow detrimental to our dignity or our welfare. And, unfortunately, those who are most extravagant in this respect are often the ones who can least afford it.
Secondly, the food which we eat does not always contain the proper proportions of the different kinds of nutritive ingredients. We consume relatively too much of the fuel ingredients of food, such as the fats of meat and butter, the starch which makes up the larger part of the nutritive material of flour and potatoes and sugar and sweetmeats. Conversely, we have relatively too little of the protein of flesh-forming substances, like the lean of meat and fish and the gluten of wheat, which make muscle and sinew and which are the basis of blood, bone and brain.
Thirdly, many people, not only the well-to-do, but those in moderate circumstances, use needless quantities of food. Part of the excess, however, is simply thrown away with the wastes of the table and the kitchen; so that the injury to health, great as it may be, is doubtless much less than if all were eaten. Probably the worst sufferers from this evil are well-to-do people of sedentary occupations—brain workers as distinguished from hand workers.
Finally, we are guilty of serious errors in our cooking. We waste a great deal of fuel in the preparation of our food, and even then a great deal of the food is very badly cooked. A reform in these methods of cooking is one of the economic demands of our time.
Cheap vs. Dear Food.—We cannot judge of the nutritive value of food by the quantity. There is as much nutriment in a pound of wheat flour as in 3 quarts of oysters, which weigh 7 pounds. There is still less connection between nutritive value and price. In buying at ordinary market rates we get as much material to build up our bodies, repair their wastes, and give strength for work in 5 cents' worth of flour or beans or codfish as 50 cents or $1 will pay for in tenderloin, salmon or lobsters.
Round steak at 15 cents a pound is just as digestible and is fully as nutritious as tenderloin at 50. Mackerel has as high nutritive value as salmon, and costs from an eighth to half as much. Oysters are a delicacy. If one can afford them, there is no reason for not having them, but 25 cents invested in a pint would bring only about an ounce of protein and 230 calories of energy. The same 25 cents spent for flour at $6 a barrel, or 3 cents a pound, would pay for nine-tenths of a pound of protein and 13,700 calories of energy. When a day laborer buys bread at 7 cents a pound, the actual nutritive material costs him three times as much as it does his employer, who buys it in flour at $6 a barrel.
Illustrations of the prejudice of people, especially those in moderate circumstances, against the less expensive kinds of food are very common.
Mr. Lee Meriwether, who has given much attention to this special subject, cites a case in point, that of a coal laborer, who boasted: "No one can say that I do not give my family the best flour, the finest of sugar, the very best quality of meat." He paid $156 a year for the nicest cuts of meat, which his wife had to cook before six in the morning or after half past six at night, because she worked all day in a factory. When excellent butter was selling at 25 cents a pound he paid 29 cents for an extra quality. He spent only $108 a year for clothing for his family of nine, and only $72 a year for rent in a close tenement house, where they slept in rooms without windows or closets. He indulged in this extravagance in diet, when much less expensive food materials, such as regularly come upon the tables of men of wealth, would have been just as nutritious, just as wholesome, and in every way just as good, save in the gratification to pride and palate. He was committing an immense economic blunder. Like thousands of others, he did so in the belief that it was wise and economical.
The sad side of the story is that the poor are the ones who practice the worst economy in the purchase as well as the use of food. The Massachusetts Bureau of Labor, in collecting the dietaries above referred to, made numerous inquiries of tradesmen regarding the food of the poor in Boston, meaning by poor "those who earn just enough to keep themselves and families from want." The almost universal testimony was, "They usually want the best and pay for it, and the most fastidious are those who can least afford it." The costliest kind of meat, the finest flour, and very highest priced butter were demanded, and many scorned the less expensive meats and groceries such as well-to-do and sensible people were in the habit of buying.
I have taken occasion to verify these observations by personal inquiry in Boston markets. One intelligent meat man gave his experience with a poor seamstress, who insisted on buying tenderloin steak at 60 cents per pound. He tried to persuade her that other parts of the meat were just as nutritive, as they really are, but she would not believe him; and when he urged the wiser economy of using them, she became angry at him for what she regarded as a reflection upon her dignity. "My wealthy customers," said he, "take our cheaper cuts, but I have got through trying to sell these economical meats to that woman and others of her class."
I am told that people in the poorer parts of New York City buy the highest priced groceries, and that the meat men say they can sell the coarser cuts of meat to the rich, but that people of moderate means refuse them. I hear the same thing in Washington and other cities.
One-sidedness of Our Dietary.—I have said that our diet is one-sided, that the food which we actually eat has relatively too little protein and too much fat, starch, and sugar. In other words, it is relatively deficient in the materials which make muscle and bone and contains a relative excess of the fuel ingredients. This is due partly to our large consumption of sugar and partly to our use of such large quantities of fat meats.
Overeating—Injury to Health.—But the most remarkable thing about our food consumption is the quantity. The American dietaries examined in this inquiry were of people living at the time in Massachusetts and Connecticut, though many came from other parts of the country. It would be wrong to take their eating habits as an exact measure of those of people throughout the United States. For that matter, a great deal of careful observation will be needed to show precisely what and how much is used by persons of different classes in different regions. Just this kind of study in different parts of the country is greatly needed. But such facts as I have been able to gather seem to imply that the figures obtained indicate in a general way the character of our food consumption. Of the over 50 dietaries of reasonably well-to-do people thus far examined the smallest is that of a mechanic's family. In this the potential energy per man per day was about 3,000 calories. The next smallest was that of the family of a chemist who had been studying the subject and had learned something of the excessive amounts of food which many people with light muscular labor consume. This dietary supplied 3,200 calories of energy per man a day. The largest was that of brickmakers at very severe work in Massachusetts. They lived in a boarding house managed by their employers, who had evidently found that men at hard muscular work out of doors needed ample nourishment to do the largest amount of work. The food supplied 8,850 calories per day.
Voit's standard for a laboring man at moderate work, which is based upon the observation of the food of wage workers, who are counted in Germany as well paid and well fed, allows 118 grammes of protein and 3,055 calories of energy. The standards proposed by myself, in which the studies of American dietaries have been taken into account, allow 125 grammes of protein and 3,500 calories of energy for a man at moderately hard muscular work. The dietaries of Massachusetts and Connecticut factory operatives, day laborers and mechanics at moderate work averaged about 125 grammes of protein and 4,500 calories of energy. For a man at "severe" work, Voit's standard calls for 145 grammes of protein and 3,370 calories of energy.
The Massachusetts and Connecticut mechanics at "hard" and "severe" work had from 180 to 520 grammes of protein and from 5,000 to 7,800 calories of potential energy, and in one case they rose to the 8,500 just quoted. In the dietary standards proposed by myself it did not seem to me permissible to assign less than 4,000 calories to that for a working man at "hard," and 5,700 for a man at "severe" work.[1]
[Footnote 1: Statistics are also given showing that the professional men of certain European countries live comfortably and have good health on much less than Americans of the same occupation.—ED.]
Now it is not easy to see why these men required so much more than was sufficient to nourish abundantly men of like occupation, but unlike temptation to overeating, in Europe. Difference in climate cannot account for it. We are a little more given to muscular exercise here, which is very well for us, but it cannot justify our eating so much.... I think the answer to this question is found in the conditions in which we live. Food is plenty. Holding to a tradition which had its origin where food was less abundant, that the natural instinct is the measure of what we should eat, we follow the dictates of the palate. Living in the midst of abundance, our diet has not been regulated by the restraints which obtain with the great majority of the people of the Old World, where food is dear and incomes are small.
Indeed, the very progress which we are making in our civilization brings with it increased temptation to overeating. The four quarters of the earth are ransacked to supply us with the things which will most tempt our appetites, and the utmost effort of cooks and housewives is used in the same direction. It is all the more fitting, therefore, that information as to our excesses and the ways of avoiding them should come at the same time.
How much harm is done to health by our one-sided and excessive diet no one can say. Physicians tell us that it is very great. Of the vice of overeating, Sir Henry Thompson, a noted English physician and authority on the subject, says:
"I have come to the conclusion that more than half the disease which embitters the middle and latter part of life is due to avoidable errors in diet, ... and that more mischief in the form of actual disease, of impaired vigor, and of shortened life accrues to civilized man ... in England and throughout central Europe from erroneous habits of eating than from the habitual use of alcoholic drink, considerable as I know that evil to be."
This is in the fullest accord with the opinions of physicians and hygienists who have given the most attention to the subject, and these opinions are exactly parallel with the statistics here cited.
Waste of Food in American Households.—The direct waste of food occurs in two ways, in eating more than is needed and in throwing away valuable material in the form of kitchen and table refuse. That which is thrown away does no harm to health, and in so far as part of it may be fed to animals or otherwise utilized, it is not an absolute loss. That which we consume in excess of our need of nourishment is worse than wasted, because of the injury it does to health. A few instances taken from the investigations mentioned above will help to illustrate the waste of food.
One of the dietaries examined by the Massachusetts Labor Bureau was that of a machinist in Boston, who earned $3.25 per day. In food purchased the dietary furnished 182 grammes of protein and 5,640 calories of energy per man per day, at a cost of 47 cents. One-half the meats, fish, lard, milk, butter, cheese, eggs, sugar, and molasses would have been represented by 57 grammes of protein, 1,650 calories, and 19 cents. If these had been subtracted, the record would have stood at 125 grammes, 3,990 calories, and 28 cents. This family might have dispensed with one-half of all their meats, fish, eggs, dairy products, and sugar, saved 40 per cent. of the whole cost of their food, and still have had all the protein and much more energy than is called for by a standard which is supposed to be decidedly liberal.
In the instance just cited no attempt was made to learn how much of the food purchased was actually consumed and how much was rejected. In some of the dietaries published by the Massachusetts bureau such estimates were made. That of a students' club in a New England college will serve as an example.
The young men of the club, some 25 in number, were mostly from the Northern and Eastern States, and coming from the class of families whose sons go to college, it seems fair to assume that their habits of eating formed at home would not differ materially from those of the more intelligent classes of people in that part of the country. While the diet of the club was substantial and wholesome, it was plain, as was, indeed, necessary, because several of the members were dependent upon their own exertions and the majority had rather limited means. Though fond of athletic sports they could hardly be credited with as much muscular exercise as the average "laboring man at moderate work." The matron, a very intelligent, capable New England woman, had been selected because of her especial fitness for the care of such an establishment. The steward who purchased the food was a member of the club, and had been chosen as a man of business capacity. He thought that very little of the food was left unconsumed. "All of the meat and other available food that was not actually served to the men at the table," said he, "was carefully saved and made over into croquettes. Men who work their way through college cannot afford to throw away their food." But actual examination showed the waste to be considerable. The estimates of the quantities of nutrients were based upon the quantities of food materials for a term of three months and upon the table and kitchen refuse for a week. The results were as follows: In food purchased, protein, 161 grammes; energy, 5,345 calories. In waste, protein, 23 grammes; energy, 520 calories. In food consumed, protein, 138 grammes; energy, 4,825 calories. One-eighth of the protein and one-tenth of the energy were simply thrown away.
During the succeeding term a second examination of the dietary of the same club was made. Another steward was then in charge. He had learned of the excessive amounts of food in the former dietary, and planned to reduce the quantities. This was done largely by diminishing the meats. He stated that he did not apprise the club of the change, and that it was not noticed. As he put it, "The boys had all they wanted, and were just as well pleased as if they had more." Estimates as before but with more care in determining the waste, showed in food purchased, protein, 115 grammes; energy, 3,875 calories. In waste, protein, 11 grammes; energy, 460 calories. In food consumed, protein, 104 grammes; energy, 3,415 calories. One-tenth of the nutritive material of the food this time was thrown away. The young men were amply nourished with three-fifths of the nutrients they had purchased in the previous term.
How much food is required on the average by men whose labor is mainly intellectual is a question to which physiology has not yet given a definite answer, but it is safe to say that the general teaching of the specialists who have given the most attention to the subject would call for little more than the 104 grammes of protein and very much less than the 3,400 calories of energy in the food estimated to be actually consumed by these young men when the second examination was made. They could have dispensed with half of all the meats, fish, oysters, eggs, milk, butter, cheese, and sugar purchased for the first dietary and still have had more nutritive material than they consumed in the second. Not only was one-tenth or more of the nutrients thrown away in each of the two cases, but what makes the case still worse pecuniarily, the rejected material was very largely from the animal foods in which it is the most expensive.
The estimates of the quantities of food in the two dietaries just quoted were made from tradesmen's bills and the composition was calculated from analyses of similar materials rather than of those actually used. The figures are therefore less reliable than if the foods and wastes had been actually weighed and analyzed. In some dietaries lately examined in Middletown, Conn., all the food has been carefully weighed and portions have been analyzed, and the same has been done with the table and kitchen refuse. The results, therefore, show exactly how much was purchased, consumed and thrown away. One dietary so investigated was that of a boarding house. The boarders were largely mechanics of superior intelligence and skill, and earning good wages; the mistress was counted an excellent housekeeper and the boarding house a very good one. About one-ninth of the total nutritive ingredients of the food was left in the kitchen and table refuse. The actual waste was worse than this proportion would imply, because it consisted mostly of the protein and fats, which are more costly than the carbohydrates. The waste contained nearly one-fifth of the total protein and fat, and only one-twentieth of the total carbohydrates of the food. Or to put it in another way, the food purchased contained about 23 per cent. more protein, 24 per cent. more fats, and 6 per cent. more carbohydrates than were eaten. And worst of all for the pecuniary economy, or lack of economy, the wasted protein and fats were mostly from the meats which supply them in the costliest form.
In another dietary, that of a carpenter's family, also in Middletown Conn., 7.6 per cent. of the total food purchased was left in the kitchen and table wastes. The total waste was somewhat worse than this proportion would imply, because it consisted mostly of the protein and fats, which are more costly than the carbohydrates. The waste contained about one-tenth of the total protein and fat and only one-twenty-fifth of the total carbohydrates of the food. At the rate in which the nutrients were actually eaten in this dietary, the protein and fats in the waste would have each supplied one man for a week and the carbohydrates for three days.
These cases are probably exceptional; at least it is to be hoped that they are. Among eight dietaries lately studied in Middletown those above named showed the largest proportion of material thrown away. In the rest it was much less. In two cases there was almost none. It is worth noting, however, that the people in these two had the largest incomes of all. In other words the best-to-do families were the least wasteful.
This form of bad economy is not confined to the kitchen, but begins in the market.... The common saying that "the average American family wastes as much food as a French family would live upon" is a great exaggeration, but the statistics cited show that there is a great deal of truth in it. Even in some of the most economical families the amount of food wasted, if it could be collected for a month or a year, would prove to be very large, and in many cases the amounts would be little less than enormous.—W.O. Atwater, Charities Review.
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THE COLORS NAMED IN LITERATURE.
Mr. Havelock Ellis has made (Contemporary Review, May) an interesting study of the color terms used by imaginative writers, which is a real contribution to scientific sthetics. The fact that the Greeks did not name green and blue does not, of course, indicate (as Mr. Gladstone and others have alleged) that they could not see the more refrangible rays of the spectrum, but it does show a lack of interest in these colors. Mr. Ellis' statistics are given in the annexed table, the number of times each of the colors is used by the author in selected passages being reduced to percentages.
- - White. Yellow. Red. Green. Blue. Black. PREDOMINANT - - Mountain of Chant 28 13 3 ... 19 37 Black, white. Wooing of Emer 34 3 48 ... ... 14 Red, white. Volsunga Saga 14 ... 71 ... 14 ... Red. Isaiah, Job, Song of Songs 18 4 29 33 ... 15 Green, red. Homer 21 21 7 2 ... 49 Black, white-yellow. Catullus 40 21 17 9 4 8 White, yellow. Chaucer 34 10 28 14 1 13 White, red. Marlowe 19 21 19 6 6 28 Black, yellow. Shakespeare 22 17 30 7 4 20 Red, white. Thomson 9 ... 18 27 9 36 Black, green. Blake 17 17 13 16 7 29 Black, white-yellow. Coleridge 21 7 17 25 14 16 Green, white. Shelley 17 19 11 21 21 11 Green-blue. Keats 14 23 24 29 8 1 Green, red. Wordsworth 14 18 10 35 11 12 Green, yellow. Poe 8 32 20 12 4 24 Yellow, black. Baudelaire 11 9 19 10 16 34 Black, red. Tennyson 22 15 27 15 10 11 Red, white. Rossetti 30 22 22 9 7 10 White, yellow. Swinburne 28 18 28 16 6 4 Red, white. Whitman 25 10 26 14 8 16 Red, white. Pater 43 19 11 11 9 7 White, yellow. Verlaine 20 15 24 9 14 18 Red, white. Olive Schreiner 38 12 25 3 19 2 White, red. D'Annunzio 15 11 46 7 14 6 Red, white. - -
Mr. Ellis makes a number of acute psychological and literary suggestions and concludes that a numerical study of color vision "possesses at least two uses in the precise study of literature. It is, first, an instrument for investigating a writer's personal psychology, by defining the nature of his sthetic color vision. When we have ascertained a writer's color formula and his colors of prediction we can tell at a glance, simply and reliably, something about his view of the world which pages of description could only tell us with uncertainty. In the second place, it enables us to take a definite step in the attainment of a scientific sthetic, by furnishing a means of comparative study. By its help we can trace the colors of the world as mirrored in literature from age to age, from country to country, and in finer shades among the writers of a single group. At least one broad and unexpected conclusion may be gathered from the tables here presented. Many foolish things have been written about the 'degeneration' of latter-day art. It is easier to dogmatize when you think that you are safe from the evidence of precise tests. But here is a reasonably precise test. And the evidence of this test, at all events, by no means furnishes support for the theory of decadence. On the contrary, it shows that the decadence, if anywhere, was at the end of the last century, and that our own vision of the world is fairly one with that of classic times, with Chaucer's and with Shakespeare's. At the end of the nineteenth century we can say this for the first time since Shakespeare died."—Science.
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WHAT THE SEA HAS TAKEN.
It was recently announced that the committee sitting under the presidency of Minister Lely, at the Hague, had determined to reclaim the Zuider Sea, and that for this purpose a dam is to be constructed from the peninsula of North Holland to the opposite coast of Friesland.
This announcement brings back to recollection the proud old Dutch proverb: "God created the sea, the Hollander the coast."
The proposal is to construct a dam from Ewyk, on the northeastern point of North Holland, to the island of Wieringen, and then from the eastern point of this island another dam, 18 miles long, to the coast of Friesland, by the shortest route.
The Hollanders, in their great reclamation works, the Sea of Harlem, for instance, prepare the entire foundation first and then gradually raise the dam on it. The watercourse is not narrowed during the progress of the work, as the dam is raised uniformly throughout the whole length; the current therefore passes slowly over it, and the dam is not subject to damage from flood waters. These deposit enormous quantities of sand and mud within the intercepted area, and after a few years the land shows above the surface of the water; the land while still in course of formation is locally known as "Heller," and the reclaimed land as "Polder."
As soon as the land has attained the required height, the dam is built sufficiently high, and also strong enough, to answer the purposes of a dike and to withstand the force of the largest tidal waves.
In constructing these dams, enormous rafts are made on the shore and then floated to the works, where they are weighted by stones and sunk in the required position. Within a few weeks large quantities of silt and mud accumulate, and the whole forms an exceedingly tough and strong elevation under the water; the currents grow weaker, and deposits are lodged also outside the dam, the base of which is of course of great width.
The Zuider Sea is one of the strongest evidences we have of the power of the sea over the land. Its formation commenced as far back as the twelfth century, prior to which it was only an inland lake. On December 14, 1287, during a terrific storm, the sea broke through the dividing shore line and widened the lake into a wide bay (Southern Sea, Dutch, Zuider Sea) of the North Sea; 80,000 persons lost their lives on that occasion. The same storm also did enormous damages in other localities.
This was, however, not the first occasion on which the sea had made inroads into the coast lands. Before the works of destruction commenced a narrow isthmus connected Great Britain with the Continent. The North Sea was then—comparatively speaking—calm; vast chains of sandy downs ran parallel to the coast, and stretched from this isthmus to the coast of Jutland; they were of considerable height, those on the west coast of Schleswig attaining an altitude of 200 feet. Behind these downs enormous swamps are formed, in which the rivers, with few exceptions, disappeared; but the deposits they brought down formed those rich agricultural lands now known locally as "Marschland."
The destruction of the shores commenced from the date that the narrow isthmus above referred to was carried away by the tidal waves which broke the English Channel during westerly gales. Traces, found far inland, show that this catastrophe occurred when the locality was inhabited, in fact a legend, in circulation to this day, relates that an English queen, to revenge herself on a Danish king, had the dam which connected England with France pierced, and so destroyed Denmark. When the Romans appeared on the scene the work of destruction was in progress, the chain of downs had been broken, and its place taken by many islands, far larger and more numerous than at present.
The first historical accounts of the storm tidal waves is referred to by Strabo as having occurred in 113 B.C., this, he relates, drove the Cimbers and Teutons from their homes and was the cause of their threatening Rome. Many other floods occurred which are known as "Manntranke" (man drowning). In the flood of 1216, for instance, 10,000 persons lost their lives, and three years later the "Marcellus" flood caused similar destruction. In 1300 the second "Marcellus" flood broke 12 feet over the highest dikes and Schleswig alone lost 7,600 persons in the waves.
Heligoland was at that time a large island, 46 miles long and 24 miles wide, it contained a monastery, many churches, large villages, extensive cultivations and forests; the island was all but destroyed by this inundation. Before that disastrous occurrence the island could be seen from the shores of Friesland, which in the days of Charles the Great was twice as large as now. The Friesland of to-day is only the southern and poorest remnant of the magnificent lands which were completely destroyed on October 11, 1684; 20 parishes and 150,000 persons disappeared beneath the waves, which broke through the dikes simultaneously in twenty-four places.
To relate all inundations would lead too far, but the most serious may be mentioned as showing the struggles in which the inhabitants of the North Sea coast are engaged. That of 1421, which swallowed 21 parishes and 100,000 persons; then the most terrible of which there is any record, and which is known as the "All Saints' Day" flood of 1570; the sea raged along the whole of the coast from Holland to Jutland for forty-eight hours, carried away all the dikes and caused the loss of 400,000 lives; the whole country lay waste for years, for the want of population to rebuild the dikes.
The Christmas flood of 1717 also visited the whole coast and 15,000 lives were lost.
During the present century the destruction by the sea has been minimized, as the dikes are now built strong and high enough to withstand the heaviest seas. The various islands along the coast act as breakwaters and protect, to a great extent, the coast line; the various governments are endeavoring to strengthen the islands by vegetation, but it appears to be only a question of time when they will disappear altogether.
Although the sea has, during the past 1,000 years, robbed the Dutch of great tracts of land, yet they have, by enduring perseverance, recovered a great deal, and there appears no doubt that they will succeed to form the Zuider Sea into rich agricultural lands, just as they have already dried up the Harlem Sea and converted it into waving cornfields.
Ground is also gained yearly in other directions, by continually extending the dikes; the richest lands on the coasts of Holland and Germany have thus been reclaimed from the ocean, and they are protected by means which secure the coasts against future encroachment.
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[Continued from SUPPLEMENT, No. 1080, page 17263.]
THE DE DION AND BOUTON ROAD MOTOR.
It was with a vehicle of the kind described in our last article that Messrs. De Dion and Bouton obtained a conspicuous success in 1894. In this competition they were the first to arrive at Mantes, doing the 36 miles in 3 hours, so that they made an average of 12 miles an hour; they were followed very closely by the Peugeot and Panhard-Levassor carriages. In spite of a series of difficult hills and bad roads, and an unintentional detour, they traversed the 48 miles between Mantes and Rouen in 4 hours 10 minutes. They recorded a speed of 15 miles an hour on some of the level roads, and on several occasions touched a maximum of 19 miles. The fact that they were able to ascend gradients of 1 in 10 at a speed of from 6 to 12 miles an hour sufficiently proved the efficiency of the machine.
The same constructors ran another vehicle in this competition of a somewhat similar design, but not adapted for a traction engine; this carried six passengers, and weighed about 3,000 lb. in working order. It was mounted on a rectangular and strongly braced frame, and was furnished with a boiler similar to that already described, but having only some 14 square feet of heating surface, a capacity of about 6 gallons of water, and 18 rows of tubes. The ratio of gearing was 4.06; the small cylinder was 3.54 in. in diameter and the low pressure cylinder 5.51 in., the stroke being 3.94 in. About the same time Messrs. De Dion and Bouton built for one of their clients a carriage in which the driving wheels were entirely independent, each of them being driven direct by a separate steam engine without any intermediate gear.
The Count de Dion was one of the most enthusiastic organizers of the Paris to Bordeaux competition in 1895, and naturally his firm took part in the trials. They entered three vehicles for competition; one of these, called No. 1, was the traction engine which had taken part in the 1894 trials, and which we have already described. For the second time this machine gave very excellent results, as it made the distance from Paris to Angoulme (280 miles) in 30 hours, but on account of various mishaps it had to run very slowly from Angoulme to Bordeaux (84 miles), taking, in fact, 31 hours for this part of the journey, and not arriving until long after it had been ruled out of the competition.
Their second vehicle, No. 2, was a four seated brake which was, in fact, a modified traction engine. The boiler, which was of the De Dion and Bouton type, had a heating surface of 36 square feet, and was registered at 200 lb. per square inch; it weighed 550 lb. As to the motor, it was a Woolfe engine, the moving parts of which were carefully counterbalanced. The cranks were set at an angle of 180; the diameter of the high pressure cylinder was 2.95 in., and that of the low pressure 5.90 in.; the low pressure cylinder was steam jacketed. This motor, which weighed 330 lb., developed 11 horse power at a speed of 800 revolutions. The engine was coupled direct to the shaft of the differential motion, on which were mounted two pinions for changing the speed, and which could be moved to and fro on the shaft; the movement of the differential gear was transmitted to the wheels by articulated shafts, such as those we have already referred to in describing the traction engine; sufficient water and coke could be carried for a run of 45 miles, and on a good road a speed of more than 25 miles an hour was obtained.
Messrs. De Dion and Bouton anticipated great things from this carriage, and for the long run from Paris to Bordeaux they had provided only three changes of drivers, in order that the machine might be in as few hands as possible. Their hopes, however, were not realized, for although it made a better start than any of the other competitors, it only succeeded in running for 125 miles; after having passed Blois the transmission shaft broke, and the brake was useless for the time being, but the machine did enough to satisfy the constructors of the soundness of their idea; it ran the 34.5 miles between Versailles and Etampes in 2 hours and 16 minutes, making an average speed of 15 miles an hour over difficult country; between Versailles and Blois the speed touched nearly 18 miles.
The vehicle No. 3 was a tricycle driven by a petroleum motor; this was not seriously entered for competition, but rather to show a first effort of a new departure which the constructors have since followed with some success. At the present time Messrs. De Dion and Bouton are making preparations to take part in the competition which is to be arranged for the autumn of the present year. They have a traction engine with considerable modifications in its design, with which they, expect to run from Paris and Marseilles, and they have the intention of hauling with it one of the 40-seat omnibuses of the Paris Company, which is usually drawn by three horses. Fig. 10 is a general view of the engine attached to the omnibus. This type of vehicle is furnished with a compound engine, which can be worked up to 30 horse power, and which is to be capable of hauling a load of 5 tons at a speed of 12.5 miles; the principal points of difference between this machine and the other, which we have already described, lie in the great care which has been bestowed on the details, the precautions taken to secure the moving parts from dust, and the oil bath in which the engine works. The water supply carried is sufficient for a run of 25 miles over an average road with a load of 3 tons; the manufacturers state that the cost of hauling this load amounts to 1d. per kilometer.
Great care has been taken as to the quality of the steel employed in the frame and other parts of the machine. By reference to Fig. 10 it will be seen that the boiler (2) is surrounded by the fuel tank, while the water reservoir forms a seat; the motor (1) is placed beneath the platform as usual. The driver has all the controlling levers conveniently at hand; the starting lever is shown at 9, while at 5 is a small wheel controlling the steam admission; the reversing gear is actuated by the lever, 7. The vehicle is steered by means of a turning bar, similar to those of hand brakes on some wagons; the feed pump is started and stopped by a small wheel marked 10, while 8 and 11 are the hand and steam brakes respectively.
We referred just now to the tricycle made by Messrs. De Dion and Bouton, and shown by them at the competition of 1895, although it was not entered for the race. Since that time they have made two types of this class of vehicle, of which we give engravings in Figs. 12 and 13. In the former the motor is attached to the back of the frame by a suspended connection. It will be seen that the frame is not a little complex, and necessarily so, in order that it may carry the different parts of the mechanism. The motor has a single cylinder and is quite inclosed in a casing that is kept filled with oil; the moving parts of the engine are within this casing; the main shaft drives, by means of a pinion, the differential gear that is mounted on the axle. It will be seen from the illustration that the builders do not rely wholly on the motor, but have provided the usual cycle pitched chain so that, in the event of a breakdown, the rider can propel his machine with the pedals. Indeed, this is always necessary in starting, though a few strokes with the pedals suffice, and as soon as the engine is started the pedal clutch is thrown out of gear. In mounting a steep gradient the pedals are also useful as an auxiliary to the motor. The mechanical power provided is sufficient to drive the machine on a good and level road at the rate of 20 kilometers an hour. It can also travel up grades of 1 in 20 or 25; the weight of the machine in working order is only 100 lb.
On referring to the engraving there will be seen attached to the frame beneath the saddle a rectangular reservoir that contains the gasoline, the capacity being sufficient for a six hours' run. To the reservoir is attached the carburetor, which is connected to the motor by a pipe. The explosive mixture in the cylinder is fired electrically, and for this purpose a compact and reliable battery is hung to the forward part of the frame almost beneath the steering bar. This battery will give 100 hours of work without recharging; it supplies current to a Ruhmkorff coil placed beneath the rear bar of the frame in a metal case that can be seen in the engraving; the other cylinder near it is a pressure reducer into which the gases from the cylinder are exhausted before they pass into the air. The second type of tricycle, illustrated by Fig. 13, is an improvement on the first. It will be seen that the frame is much simpler; the total weight is reduced; the gasoline reservoir is triangular, in order to economize space. The motor employed is very ingenious, and appears to be efficient; we have seen it in operation at the works of MM. De Dion and Bouton. It can be run easily at a speed of 2,500 revolutions, although in practice the rate is limited to 700 revolutions, in order to reduce the wear of the moving parts. In this, as in the earlier type, the use of water for cooling the cylinder is avoided, the outside of the latter being made with a number of wings that are intended to keep the cylinder cool by contact with the air. The method of igniting the gases has also been changed, in so far as the arrangement of the battery is concerned. The four cells used for this purpose are carried in a leather case hung to one of the frames of the machine. An interesting detail is that the exact moment for producing the spark is regulated by the motor itself, and the Ruhmkorff coil is suppressed. The contact breaker has been placed on the motor, and a cylindrical cam is mounted on the shaft that controls the exhaust valve. In this cam there is formed a recess into which the blade of the contact breaker, which is fixed on an insulated mount, falls at the proper instant; at the same moment the spark is produced, the blade being raised as it leaves the recess in the cam. It is, of course, necessary to regulate exactly the relative positions of the blade and the cam, so that the spark may take place when the mixture has to be exploded. The frame of the motor is of aluminum, by which considerable saving in weight is effected; as in the earlier model, the moving parts of the motor are immersed in an oil bath. The pedals are employed to start, or as an auxiliary, or in the event of a breakdown. When not required for propulsion, they are thrown out of gear, when they serve as foot rests, and also as a means for actuating an emergency brake. The carburetor is no longer attached to the gasoline reservoir, but is separate; the explosions in the cylinder are regulated by a lever close to the steering bar.
The greatest credit must be accorded to MM. De Dion and Bouton for the perseverance and ingenuity they have shown in the design and construction of the types of power vehicle they have made their own. As to their larger carriages, experience has proved their practical value; they have expended even more trouble on their power cycles, but it appears to us that ingenuity and skill are largely wasted in this direction, since the raison d'etre of the cycle in all its forms lies in the fact that it should give perfect freedom to the rider and leave him dependent for his progress upon his own efforts.—Engineering.
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FROM NEW YORK TO HAVRE IN A ROWBOAT.
The rowboat Fox, of the port of New York, manned by George Harbo, thirty-one years of age, captain of a merchantman, and Frank Samuelson, twenty-six years of age, left New York for Havre on the 6th of June. Ten days later the boat was met by the German trans-atlantic steamer Frst Bismarck proceeding from Cherbourg to New York. On the 8th, 9th and 10th of July, the Fox was cast by a tempest upon the reefs of Newfoundland. The two men jumped into the sea, and thanks to the watertight compartments provided with air chambers fore and aft, it was possible for them to right the boat; but the unfortunates lost their provisions and their supply of drinking water. On the 15th they met the Norwegian three masted vessel Cito, which supplied them with food and water. The captains of the vessels met with signed the log book and testified that the boat had neither sail nor rudder. The Fox reached the Scilly Islands on the 1st of August, having at this date been on the ocean fifty-five days. It arrived at Havre on the 7th of August.
Cost what it might, the men were bent upon reaching this port in order to gain the reward promised by Mr. Fox, of the Police Gazette. Thanks to the wind and a favorable current, they made 125 miles in 24 hours. One slept three hours while the other rowed. Their skins and faces were tumefied by the wind, salt water and sun; the epidermis of their hands was renewed three times; their legs were anchylosed; and they were worn out.
The boat was 18 feet in length, 5 in breadth, and 23 inches in depth, and carried a small kerosene stove for cooking.—L'Illustration.
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THE WASTE OF SHIPPING.
Burdensome as are the restrictions imposed upon shipowners by legislation, considerable justification is found for them when we compare the percentage of British vessels lost at sea with that of foreign-owned vessels. The great shipping countries, that is, those which have more than 1,000,000 tons afloat, are the United Kingdom, the British colonies, the United States of America, France, Germany and Norway. Of these six the United Kingdom suffered the least comparative loss in its mercantile fleet in 1895. Under all the heads of abandoned at sea, broken up or condemned, burnt, collision, foundered, lost, missing and wrecked, the total loss was 2.99 per cent. of the vessels owned and 2.36 per cent. of the tonnage owned. No other of the countries named has less than 3 per cent. of loss, while only the British colonies have less than 4, as the subjoined table shows.
TOTAL LOSSES OF STEAM AND SAILING VESSELS IN 1895.
+ Vessels Owned. Percentage Lost. + -+ -+ Flag. Vessels Tonnage No. Tons.[1] Owned. Owned. -+ + United Kingdom. 9227 12,117,957 2.99 2.36 British Colonies. 2307 1,124,682 3.38 3.70 United States of America. 3220 2,164,753 4.72 4.06 French. 1164 1,094,752 6.01 4.02 German. 1730 1,886,812 6.76 4.38 Norwegian. 3041 1,659,012 7.43 6.46 -+ + -+ -+ -+
[Footnote 1: Gross tonnage for steamers; net for sailing vessels.]
When we turn from the contemplation of the complete fleets, and differentiate between steam and sail, we find that the United Kingdom no longer holds the premier position, being surpassed, as regards steam, both by the colonies and by the United States. Steam vessels are safer than sailing craft all over the world, partly, of course, because their average age is less. The losses they suffered last year are as follows:
TOTAL LOSSES OF STEAM VESSELS IN 1895.
-+ + -+ Vessels Owned. Percentage Lost. + + -+ -+ Flag. Vessels Tonnage No. Net. Gross. Owned. Owned. -+ + -+ -+ -+ -+ United Kingdom. 6446 5,993,666 9,695,976 3.33 2.13 British Colonies. 874 329,845 542,025 1.72 1.69 United States of America. 626 660,784 920,672 2.23 1.93 French. 571 467,553 903,105 4.20 3.42 German. 953 910,567 1,343,357 3.04 2.64 Norwegian. 586 285,349 446,384 2.56 2.87 -+ + -+ -+ -+ -+
The United Kingdom here stands third in the list, and curiously it only stands second under the head of number of sailing ships lost, while it is first as regards sailing tonnage lost. The sailing tonnage of the United Kingdom is only about 20 per cent. of the total, while in the colonies it is about 52 per cent. The following are the figures:
TOTAL LOSSES OF SAILING VESSELS IN 1895.
-+ -+ -+ Vessels Owned. Percentage Lost. + -+ -+ -+ Flag. Vessels Tonnage No. Tons. Owned. Owned. -+ + + -+ -+ United Kingdom. 2781 2,421,981 4.53 3.27 Colonies. 1435 582,657 4.39 5.56 United States of America. 2594 1,244,081 5.32 5.63 French. 593 191,647 7.76 6.83 German. 777 543,455 11.33 8.66 Norwegian. 2455 1,212,628 8.59 7.78 -+ + + -+ -+
The losses of sailing vessels are very serious among the Continental nations, especially in Germany, where more than one in nine was lost or condemned last year. This is greatly due to the fact that our old ships are largely sold to the foreigner when they will no longer comply with legislative conditions of this country. We break up a few, but only 0.75 per cent., against 1.75 per cent. for Norway and 2.5 per cent. for France and Germany. We are more chary of breaking up our steamers; last year only 0.46 per cent. met this fate here, 0.34 per cent. in the colonies, 0.32 per cent. in the United States, 0.86 per cent. in France, 0.31 per cent. in Germany, while Norway did not lose a single steamer in this way.
Turning now to the present year we find that in the first quarter the vessels lost, condemned or reported missing before August 7 were, according to returns made out by Lloyd's Register of British and Foreign Shipping, 282 vessels, of an aggregate of 195,480 tons. These figures are respectively 23 per cent. and 24 per cent. of the total losses last year, thus showing a favorable beginning, for the winter losses are naturally the heaviest. The materials of the vessels lost were: Steel, 24 vessels of 40,474 tons; iron, 74 vessels of 78,314 tons; and wood and composite, 184 vessels of 76,692 tons. The United Kingdom shows best under the heads of total losses and losses of sailing vessels, but in steamers it actually comes last among the six nationalities we have selected for comparison. It must be remembered, however, that the British fleet is large enough for a very fair average to be attained in three months, while in all other fleets a single loss, more or less, makes a great difference to the figures of merit. The steam tonnage of the United Kingdom is more than seven times greater than that of Germany, which is our chief competitor. In sailing tonnage we do not hold this immense superiority, our amount being only about double that of the United States and of Norway respectively.
When we examine the various causes of loss of vessels at sea, we find nearly 43 per cent. of the tonnage under the head of "wrecked," which includes vessels lost through stranding, or through striking rocks, sunken wrecks, etc. Next come 22 per cent. broken up or condemned; 14 per cent. lost, missing; 8 per cent. lost by collision; 4.3 per cent. burnt; 5 per cent. abandoned at sea; and 3.6 per cent. foundered. The following table shows the mercantile marine of the world, according to Lloyd's Register, at the end of March, 1896:
Flag. Steam and Sailing Vessels Owned.
No. Tons. British. /United Kingdom. 9227 12,117,957 Colonies. 2309 1,124,682 America, United States of. 3220 2,164,753 Austro-Hungarian. 309 304,970 Danish. 812 356,714 Dutch. 458 446,861 French. 1164 1,094,752 German. 1730 1,886,812 Italian. 1239 778,941 Norwegian. 3041 1,659,012 Russian. 1086 487,681 Spanish. 748 554,238 Swedish. 1432 497,877 Other European countries. .... ......... Central and South America. .... ......... Asia. .... ......... Other countries. .... .........
—Engineering.
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NEW METHODS OF BUILDING CONSTRUCTION AT PARIS.
During recent years an interesting change has been gradually brought about in the various methods of building construction employed in France, and more especially at Paris, where the size and importance of public buildings and the many-storied houses divided up into flats necessitate special systems of construction, which possess the advantages of combining economy in cost with strength and durability. Parisian architects and builders, although far from approving the extremes to which their American confrres go in the employment of iron for the construction of their somewhat exaggerated sky-scraping buildings, in which the style of architecture employed is often scarcely logical or consistent with the modern methods of construction, are nevertheless obliged to own to the necessity and the utility of employing iron in moderation for the framework of their buildings. Up to the present the use of iron in its ordinary form has chiefly been confined to floors, partitions, and roofs, where, as a rule, its presence is masked by coverings of cement, wood, or stone, except in recent examples of the new style of buildings destined for brasseries or drinking halls, where the iron construction is left visible, and emphasized by means of bronze or color painting and mosaic work, or, again, in the few examples of well known work where the architect has endeavored to obtain a decorative effect by means of iron lintels and columns. But where the use of iron is fast finding favor at Paris is in its employment in combination with other materials such as cement or concrete, and in a special form known as the cement arm systems, in which iron or steel is employed in the form of thick wire, trellis, or light bars embedded in cement or concrete. This method of construction, of which there are three different systems, has for some time been employed in the construction of various buildings of more or less importance, and has given proof of its strength and practical use as well as its advantages when employed for floors, partitions, walls and roof, both as regards its conveniences for internal arrangements, its economy, and as regards the manner in which it lends itself to modern schemes of polychrome decoration.
Two of these systems have been employed by the architect of the new building now being constructed in the Rue Blanche for the Society of Civil Engineers of France. The third system is much employed by M. De Baudot in various buildings designed by this architect, an advocate of rational construction and design and the logical employment of modern building materials. It will be interesting to examine the merits of each system as employed in these buildings, together with any other points of construction worthy of remark.
The building for the Society of Civil Engineers is remarkable from several points of view as regards construction and the arrangement of plan. The faade and plans will appear in the Building News as soon as the work is completed, and will form an interesting subject for comparison with the building recently completed for the English Society of Engineers, and with that about to be commenced at New York for the American Society.
Before entering into a detailed description of the system employed, a summary idea of the plan and general scheme of construction will not be uninteresting. The architect, M. Fernand Delmas, has endeavored to construct the building on economical lines, employing to a large extent iron and those modern materials which have been tried and found fitting as regards suitability and economy; the building will cost 22,000, and it has been made a sine qua non that all the contractors shall be members of the Society of Engineers.
The length of the faade is 100 ft.; the total depth of the building is nearly equal to the frontage; the height from pavement to cornice is 60 ft. The faade is built of solid stonework throughout its length and height. The thickness of the masonry is 24 in. at the lower stories and 18 in. at the upper portion. The faade wall is really the only portion of solid masonry work in the whole building, and forms a decorative mask to the body of the building, which is constructed of a framework of iron. The chief supports of the building proper consist of four framed iron uprights, 16 in. by 16 in. rising from the basement to the roof. These uprights are solidly trussed and held together at the floor levels by strong iron girders supporting the iron joists of the upper floors and the light partitions which divide up each story. This system is at once economical and practical. The whole building is thus self-supporting, and the thick walls which would otherwise be necessary for carrying the upper floors are thus avoided.
The faade wall is built according to the system always employed at Paris, and is formed of blocks of stone roughly cut at the quarries to the outside dimensions of the proposed moulding and decorative work. As soon as the whole front is erected the work of cutting it into shape will commence, the mouldings, pilasters, and all carving work being done while the interior is being prepared. The buildings at Paris are by this means erected much more rapidly than when the stone is dressed or moulded before being put into place. Greater facilities are thus given for studying the general ensemble of the faade and the proper scale to be given to the mouldings and decoration. The stone is as a rule soft when first from the quarries, but becomes hard and durable after dressing and exposure to the air. The courtyard wall of the building is formed of light brick or metallic fillings between the iron uprights and the party walls.
The ground floor comprises a large entrance hall or vestibule, 40 ft. by 44 ft., forming, with the cloakroom, the principal staircase, the rooms for the concierge, and the area, the whole front of the building. This large vestibule is vaulted over by means of one of the systems of cement arm to be described. The floor is constructed on another similar system, and will be paved with mosaic work. The ground floor of the courtyard will be occupied by the conference hall, 50 ft. by 50 ft., to hold 300 seats. An annex, 50 ft. by 20 ft., adjoining this hall, will open on the same by a large arched bay, and may be separated from the larger hall by means of a special system of wooden soundproof roller shutters. The floor of the large hall will be a movable one, to be raised or lowered by an ingenious system of hydraulics, and capable of being placed in an inclined position for conference meetings, or raised to a horizontal position for ball room purposes.
The entresol floor will comprise a large room for meeting, smoking and conversation rooms, and a reading room, to be used as a club for the members of the society. The first floor will contain the offices of the society, a large committee room, and all conveniences. The second floor will be devoted entirely to the purposes of the important library, comprising the library proper, a room 45 ft. by 25 ft. by 17 ft. high, rising to the ceiling of the low story above, and lighted by a large semicircular bay at either end: the surrounding rooms of the height of the second floor will be destined for the librarian, catalogues, drawing office, and library offices. The third floor will be devoted entirely to the purpose of storing the books of the library, in low rooms communicating by means of the gallery overlooking the library below, which will be crossed by means of a light, iron bridge. The bookcases will be suspended from the upper floor, and will be arranged in vertical tiers hung on rollers, after the system employed at the British Museum. The roof story will be divided up into an apartment for the chief secretary, and reached by a private staircase from the ground floor. The large basement, occupying the whole of the ground surface of the building, will be used for storing the records of the society, and will contain the heating apparatus, stores, etc. A hydraulic lift will afford access to the landings of each floor. The chief feature of the faade, which is simple in style, is the wide arched bay, 24 ft. across, rising from the pavement to above the cornice; this bay will be filled in with an open decorative framework of wrought and cast iron.
Some of the most interesting points of the construction, besides the large use of iron, are the systems employed in the construction of the floor. The ground floor is built after the Coignet system, composed of light iron bars and cement; the first floor and its supporting pillars and arches is constructed after the Hennebique system of cement arm; the upper floors are formed of iron joists, filled in either with the system of light supports and plaster, much employed at Paris, or with terracotta fillings between joints. The roof is lined internally with agglomerated cork bricks, affording protection from excessive heat or cold, and the walls of the area will be lined with opaline, a vitreous material of a bluish white color, which in this case will insure cleanliness, and afford additional light; the lavatories and water closets will also be lined with the same material.
Speaking of the Hennebique system of cement arm, employed for the arches and floor of the first story, it will be interesting to illustrate the method by a few sketches, explaining the theory of this system, which has been put to practical proofs in a large number of buildings, chiefly for industrial purposes, in the north of France. The perspective section will give an idea of the construction as employed in the building for the civil engineers, a system which holds its ground well against its rivals of other methods of cement arm.—The Building News.
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BELLEEK CHINA.
Belleek porcelain (frequently pronounced "Bleak" by those who do not know the derivation of the name) is a thin eggshell ware of great lightness and translucency, characterized by a creamy, or sometimes grayish, tint, and usually covered with a delicate pearly or lustrous glaze. It is in reality a variety of Parian ware, being formed in the same manner by the process called casting, or pouring diluted clay or slip of the consistency of cream into plaster moulds, which, by absorbing a part of the moisture from the portion of the liquid preparation in direct contact, retain a thin shell of partially dried clay after the superfluous contents are taken out. After standing a few minutes the thin cast can be liberated from the mould. The thickness of the walls, of course, depends upon the length of time the slip is allowed to remain in the mould before the surplus is removed. By this ingenious method cups, saucers and other forms of ware can be made almost as thin as an egg shell or a piece of heavy paper, and after being allowed to become thoroughly dry can be safely burned in the kiln. It can readily be understood that it would not be possible to make such fragile pieces by the usual processes with plastic clay, which must be of the consistency of putty or dough, on the potter's wheel or by pressing in moulds.
Belleek ware was first made at Stoke upon Trent by the eminent potter William Henry Goss, who invented the body or composition some thirty-five years ago; but it was not then known by this name. Soon after its introduction Messrs. McBirney & Armstrong induced some of Mr. Goss' workmen, including his manager, William Bromley, to join them at their porcelain works, then recently started (in 1863) in the town of Belleek, County Fermanagh, Ireland, and the art was established so successfully there that the name of the village was given to the ware which has since become so noted. The distinguishing characteristic of this beautiful product is its lustrous glazing, which varies in form from white to yellow and through graded tints to a dark leaden hue.
Mr. Goss has continued to manufacture this dainty variety of porcelain until the present time, and his factory has become one of the most noted in the British empire. Among the most popular of his productions in this body are loving cups and little cream jugs, cups and saucers, and fairy tea sets embellished with beautifully colored crests and coats of arms of the different English cities and of prominent personages, such as Queen Elizabeth, Sir Walter Raleigh, King Henry of Navarre, Queen Victoria, the Prince of Wales, Shakespeare, Sir Walter Scott, and Robert Burns.
Of more interest, perhaps, to Americans are the porcelain tumblers which have just been produced at the same factory, bearing on the front a faithful duplication in blue and yellow enamels of the insignia of the society of Sons of the Revolution, which were made at the suggestion of a member of the society in Pennsylvania. The soft, satiny Belleek body seems to be particularly well adapted to show off to advantage the rich designs of these badges, and this suggestion will doubtless be followed by other patriotic hereditary societies in the United States.
John Hart Brewer, of Trenton, first attempted the manufacture of Belleek ware in this country. He commenced his experiments in this line in 1882, and in the following year brought over from England William Bromley and his son from the Belleek works in Ireland. Subsequently the elder Bromley joined the Willets Manufacturing Company, of the same place, and introduced the manufacture of eggshell porcelain there, and at the present time there are no less than five or six establishments in Trenton where the same class of ware is made.
Among many specialties recently introduced is a new style of decoration which has been worked out by Miss Kate Sears, a Kansas girl who studied modeling in Boston. Going to Trenton for the purpose of pursuing her studies in this direction, one day in 1891, while engaged in working over the wet Belleek, the idea of carving delicate designs in the dry clay occurred to her, and after conducting a series of experiments her efforts were crowned with success. The process of modeling which Miss Sears has originated is as follows: A vase or other piece which has been formed in the wet clay and dried is taken before it has been in the kiln, and with knives or other tools the design is cut or chiseled so as to leave the background as thin and transparent as possible when finished. As the dry Belleek, besides being thin, is extremely brittle, and crumbles easily, the carving is an exceedingly difficult operation. It is necessarily a very slow process, since at any moment the knife is liable to cut through the wall and ruin the piece.
The result of this process is a clear cut, chiseled effect, which cannot be obtained by moulding or casting, a moonlight effect of fairy like character, most beautiful in conception, and possessing marked originality. While sometimes several weeks are consumed in executing a single piece of the carved ware, Miss Sears has produced a large number of such designs, each one of which is a perfect work of art, reflecting credit upon the artist and the manufacturers.
The marks which appear on the various productions of Belleek porcelain are of considerable interest to collectors and admirers of this beautiful ware. Mr. Gross has adopted as a factory mark his family crest, a falcon rising ducally gorged, which is printed on each piece in black. The mark of the Belleek factory in Ireland, consists of the four Irish emblems, the watch tower, the hound, the harp of Erin, and the shamrock, and is printed on the ware in green or black. At the Etruria Pottery, formerly operated by Messrs. Ott & Brewer, now known as the Cook Pottery Company, the mark used on Belleek ware was a crescent bearing the name with the initials of the proprietors, "O. & B." The Willets Manufacturing Company uses for a factory mark on its decorated Belleek pieces the figure of a serpent looped in the form of a W, which is printed in red. On similar ware produced by the Ceramic Art Company is printed in red a design composed of a painter's palette and a circle inclosing the monogram C. A. C., while Messrs. Morris and Willmore, of the Columbian Art Pottery, employ a shield with the initials of the firm name, M. W.
The manufacture of Belleek ware was introduced into this country by English potters who had learned the processes at the potteries in England and Ireland, and we cannot, therefore, lay claim to originality so far as the product itself is concerned; yet, in a measure, the ware as made in America differs materially from the foreign in many respects, and has been developed in new directions, so that it has come to have distinctive characteristics of its own which entitle it to be ranked with original American productions. While our potters, perhaps, have not yet reached the high degree of elaborate modeling which characterizes some of the imported Belleek, they have already surpassed the foreign manufacturers in the simplicity and elegance of their forms and the artistic quality of their decorations, while in delicacy of coloring, in the excellence and lightness of body, the American products are not surpassed. A visit to the showrooms of the Trenton potteries will prove a revelation to those who still believe that no artistic china is made in this country.—Edwin Atlee Barber, in China, Glass and Lamps.
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GOODMAN'S HATCHET PLANIMETERS.
The instrument we are about to describe is an improvement on the hatchet planimeter and is due to Prof. Goodman, of Leeds. One form of the instrument is intended for the measurement of areas of surfaces, and the other form for the measurement of the mean height of a figure such as an indicator diagram.
London Engineering, to which we are indebted for the cuts and copy, describes the instruments as follows: The method of using the two instruments is practically the same, but for the present we shall confine our remarks to the instrument for measuring areas. In order to familiarize oneself with the peculiar action of the instrument, it will be well to get a large sheet of paper on a drawing board or a large blotting pad, and holding the instrument vertical to the paper, grasp the tracing leg very lightly indeed between the forefinger and thumb of the right hand, with the hatchet toward the left hand, as shown in Fig. 1. Then by moving the tracing point round and round an imaginary figure and allowing the hatchet to go where it pleases, it will be seen that the hatchet moves to and fro along zigzag lines, and travels sideways—the side travel being nearly proportional to the area of the figure described by the tracing point. If the tracing point be too tightly grasped, the hatchet will not move freely, and, will have a side slip. When this occurs the side travel of the hatchet ceases to be proportional to the area traced out. A loose weight is hung on the hatchet to prevent this side slip, but as soon as a little skill is attained in the use of the instrument, this weight may be dispensed with.
When measuring the area of such a surface as that inclosed by the boundary line shown in Fig. 3, a point, A, is chosen somewhat near the center of the figure; the exact position is, however, immaterial. From the point, A, a line, AB, is drawn in any direction to the boundary; the tracing point of the planimeter is now placed at A, with the hatchet at X, Fig. 3, that is, with the instrument roughly square with AB. The hatchet is now lightly pressed in order to mark its position on the paper by making a slight dent, then leaving the hatchet free to move as shown in Fig. 1, the tracing point is caused to traverse the line, AB, and the boundary line in a clockwise direction, as shown by the arrows, returning to A via AB. The hatchet will now be found to have taken up a new position, Y, which must be marked by again pressing the hatchet to make a slight dent in the paper. If the figure under measurement be on a separate sheet of paper, the paper must now be revolved about the point, A, through about 180 deg. (by eye), using the tracing point of the instrument as a center, care being taken that neither the point nor the hatchet be shifted while the paper is being turned. The line, AB, will again be roughly at right angles to the instrument, but in the reverse direction (see dotted lines in Fig. 3). Again cause the tracing point to traverse the line, AB, and the boundary line as before, but this time in a contra-clockwise direction. The hatchet after this backward motion will take up the new position, X1, which may or may not coincide with X; if not, prick a central point between X and X1, as shown, then, of course, the distance of this point from Y is the mean side shift of the hatchet; this distance measured from the zero of the scale on the back of the instrument is the area of the figure in square inches. The scale is read in exactly the same manner as a geometrical scale on a drawing, the whole numbers being read to the right of the zero and the decimals to the left. The instrument does not profess to give results nearer than one-tenth of a square inch.
In some cases on large maps, for example, the figure cannot be turned round as indicated above; in that case the instrument itself must be turned round through 180 and two fresh dents, XY, obtained; the area of the figure is then the mean of the two readings, XY and XY.
When the area is large the instrument will move through a large angle, and consequently, if square with AB to start with, it will be considerably out of square at the finish. In such a case it is only necessary to see that the mean position of the instrument is square with AB.
By carefully examining the scale it will be observed (see Fig. 1) that the divisions are not equal, but that they gradually increase from zero upward; herein consists the improvement of this instrument over the ordinary hatchet planimeter invented by Knudsen, of Copenhagen, who shows in a pamphlet published by him that
c1 + c2 I = ——————- p [1 - (R / 2p)] 2
Where I = the area traced out by the pointer in square inches.
c1 = the distance between the dents, X and Y, in inches.
c2 = the distance between the dents, X1 and Y, in inches.
p = the length of the instrument from center of hatchet to point in inches.
R = the mean square of the radii of the figure.
The making of such a calculation for every area measured is, of course, quite out of the question. The labor involved would be as great as calculating the area by the ordinate or by Simpson's method; hence it is usual to neglect that part of the formula inclosed within the square brackets, which amounts to assuming the area to be equal to the product of the mean side shift of the hatchet by the length of the instrument; this, however, involves an error too big to be neglected, and, moreover, one that is not a constant fraction of the area measured, thus:
Area of circle, square inches. 10 20 30 40 Error per cent. 0.8 1.6 2.4 3.2
These errors are, however, compensated for in Goodman's improved instrument by making the scale with constantly and regularly increasing divisions. If, however, the area dealt with be not a circle, the error involved in assuming that its R is equal to the R of a circle of equal area is so small that it is quite inappreciable on a scale which only reads to one-tenth of a square inch. If the R for any given area were say 5 per cent. greater than that of the equivalent circle, the error involved would be 0.0016 of the whole quantity when measuring an area of 40 square niches, or 0.064 square inch, a quantity which cannot be measured on the scale. It has been proposed to use a roller and vernier to enable the readings between the dents to be measured with a greater degree of accuracy, but it will be readily seen that the instrument is not reliable to the second place of decimals, hence such refinements are only imaginary. Even with this special scale that we have described above, the inventor does not profess to get as good results as with an Amsler planimeter; he regards his instrument as equivalent to a foot rule in comparison with a micrometric gage as representing Amsler's instrument; but for a great number of purposes the foot rule is sufficiently accurate, and only when great accuracy is required will a micrometer be used, so with the two forms of planimeter. The rougher instrument has some advantages, however; there are no delicate moving parts to get out of order, and the cost is but one-fourth.
In order to ascertain the relative accuracy of various methods of measuring areas, Prof. Goodman has had a large number of irregular areas measured by his first year students within a week or so of their entering the department, before they have attained to any degree of skill in using instruments. The results were as follows. Amsler's planimeter was taken as the standard, the area measured by it being independently checked by an assistant.
Measurement of Areas Method. Reduced to 100. Amsler planimeter 100 Goodman " 100 + or - 0.6 Simpson's rule 100 + or - 1.0 Mean ordinates 100 + or - 2.4 Cutting out in cardboard and weighing against piece of known area 100 + or - 4.4 Equalizing curved edges by drawing straight lines along boundary and calculating by triangles 100 + or - 7.0
In the averaging instrument for getting mean heights of figures, the length of the instrument between the hatchet and the pointer is variable. The length is set to the length of the diagram (see Fig. 2); it is then used in precisely the same manner as the planimeter described above. From what we have already said, our diagram in Fig. 5 will be perfectly clear. The mean distance between the dents is in this case the mean height of the diagram, measured on an ordinary scale, or the mean pressure in the case of an indicator diagram measured on a scale to suit the indicator spring.
Knudsen's formula given above applies equally well to this averaging instrument. Neglecting for the moment the quantity in the square brackets, we have I = c p where c = (c1 + c2)/2 but we also have I = h l where h is the mean height and l the length of the figure, therefore h l = c p; but in this instrument we make p = l. Hence h = c, or the mean height of the figure is equal to the mean distance between the dents. The quantity in the brackets is too great to be neglected, however. If we were always dealing with circles, the ratio (R/2p) would be a constant, and numerically equal to 1/16 or 6.25 per cent. Then all we should have to do would be to use a scale 6.25 per cent. longer than the true scale. But with a long narrow figure such as an indicator diagram, this ratio is much smaller. The measurement of a large number of diagrams gave a mean value of 1/60 for diagrams 4 in. long. It is obvious that, if a diagram be shortened, this ratio will increase, for the value of R does not decrease as rapidly as p, and vice versa; hence this ratio varies approximately inversely as the length of the diagram. Taking the value of 1/60 for the 4 in. diagram, this is equivalent to saying that there is an error of 1 in 60, or 1.67 per cent., in the result, and from the formula it will be seen that the result is too great by this amount; hence, if we make the length, l, between the legs of the instrument 1.67 per cent. of 4 in., or 0.067 in. less than the length from the tracing point to the center of the hatchet, p, we shall compensate for the error on a diagram 4 in. long. But the ratio of this constant quantity 0.067 in. to the length of the diagram also varies inversely as the length in just the same manner as the ratio R/2p, hence this method of correcting the instrument is approximately right for all lengths of diagrams. It must be remembered that if this correction were entirely neglected, it would not exceed two per cent.; hence any inaccuracy in this correction is an exceedingly small quantity, well under 1 per cent.
Whenever errors have been attributed to the instrument, on examination it has always been found that they were due to carelessness in setting the length to the diagram, or to the tracing leg having been grasped so tightly as to cause side slip.
The accuracy of the instrument may be easily demonstrated by drawing a rectangle, say about 4 in. long and 2 in. high, and finding the mean height by the averager, then by doubling the paper over and comparing its height with the mean distance between the dents, it will be found that they agree if the instrument has been carefully used.
In many quarters we know that there is a great deal of prejudice against instruments of this kind. We are quite sure, however, that if only draughtsmen and others would spend half an hour in trying them over, they would save themselves many hours of tedious labor in calculating areas by methods which are seldom as accurate as the results obtained by a planimeter in the same number of minutes.
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APPARATUS FOR THE MANUFACTURE OF ACETYLENE GAS.
We give herewith, from Le Genie Civil, illustrations and brief descriptions of some of the more prominent apparatus used for the manufacture of acetylene gas.
Trouv Apparatus (Fig. 1).—The principle of the gas generator is that of the hydrogen briquet already applied by Mr. Trouv in his portable lamp. It consists of two vessels, one entering the other. The internal vessel is provided at the bottom with a discharge pipe communicating, through a cock, with the gasometer. It carries a suspended open work basket containing the carbide of calcium. The bottom of this vessel is provided with an aperture through which it communicates with the external vessel containing the water. The latter is brought to a level in the two vessels and attacks the carbide. The acetylene formed is disengaged and enters the gasometer. At the same time, the excess of pressure forces back the water into the external vessel in suppressing its contact with the carbide. The latter, nevertheless, continues to be attacked slowly through the action of the aqueous vapor. If the cock of the apparatus now be closed, the gas will accumulate in the interior vessel and will soon escape through the aperture in the bottom in raising the column of water. Mr. Trouv has endeavored to remedy this inconvenience by arranging the pieces of carbide in the basket in distinct layers separated by disks of glass. He has, besides, provided his apparatus with an electric alarm, designed to give warning when the holder is too full or when it is on the point of being empty.
Clauzolles Apparatus (Fig. 2).—This apparatus consists of a gas generator, A, hermetically closed and containing the carbide, of a water reservoir, B, communicating with A through a cock, H, and of a gasometer, D, connected with A by the tube and cock, A. The cock, H, is provided with a lever fixed by its extremity to a chain that follows the motions of the holder. When the latter rises or descends, it causes the cock, H, to close or open.
The receptacle, A, is held by a cover fixed by means of four nuts which are removed when it becomes necessary to renew the carbide. The receptacle is removed and replaced by a duplicate one, after the cock, K, has been closed so as to keep the gas in the gasometer.
Bon Apparatus (Figs. 3 and 4).—The acetylene is produced by the reaction of the water falling in small quantity upon the carbide contained in the gas generator, A. The latter is divided into compartments, F, which, filled with carbide, are reached by the water only successively and progressively. When the carbide of the first compartment is exhausted, the water enters the second, and so on. The dimensions and numbers of these departments vary with the size of the apparatus. Each of them contains from lb. to 4.5 lb. of carbide. The box with compartments, F, is covered by a rectangular holder, H, which enters a flat-bottomed receptacle, E, opened above and filled about two-thirds full of water. The latter serves as a hydraulic joint, and, at the same time, as a refrigerator. The holder, H, carries a lead pipe, G', terminating in a funnel into which falls the water from the reservoir, C, led by the pipe, G. This water flows through the extremity, i, of the pipe, G', into the first compartment. Each of the compartments carries, upon the top of the partition that separates it from the following, an aperture through which the water enters the adjoining compartment as soon as the gas in the preceding compartment has made its exit from the gasometer, and so on until the last in the order of the numbers of the compartments.
The flow of the water through the pipe, G, is regulated automatically by a cock, r', with counterpoise. The holder, in rising, closes this cock and gradually cuts off the entrance of the water. The gas produced, once consumed, the holder descends in opening the cock, and the water begins to flow again.
The disengaged acetylene enters the gasometer, B, through the pipe, D. The extremity of the latter is bent into the form of a swan's neck. The gas is thus forced to bubble up through about 2 in. of water, in which it is cooled and freed from all traces of the ammonia that it may contain. The cock, R, in the pipe, D, is a three-way one. The first opens and the second intercepts communication between the gas generator and the gasometer, while the third puts these two parts of the apparatus in communication with the atmosphere.
The total capacity of the gasometer is so calculated that the acetylene produced by a single one of the compartments, F, may be stored up therein upon its exit from the gasometer through the pipe, K. The acetylene traverses a purifying column, I, filled with pumice stone saturated with a solution of sulphate of copper and surmounted by a thin layer of carbide of calcium. The object of the sulphate of copper is to free the gas from phosphorus and arseniuret of hydrogen. The layer of carbide serves to dry it. |
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