SCIENTIFIC AMERICAN SUPPLEMENT NO. 363



NEW YORK, DECEMBER 16, 1882

Scientific American Supplement. Vol. XIV, No. 363.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

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TABLE OF CONTENTS

I. ENGINEERING AND MECHANICS.—The New York Canals.— Their history, dimensions, and commercial influence

Cottrau's Locomotive for Ascending Steep Grades.—1 figure

Bachmann's Steam Drier—3 figures

H. S. Parmelee's Patent Automatic sprinkler.—2 figures

Instrument for Drawing Converging Straight Lines.—10 figures

Feed Water Heater and Purifier. By GEO. S. STRONG.—2 figures

Paper Making "Down East."

Goulier's Tube Gauge.—1 figure.-Plan and longitudinal and transverse sections

Soldering Without an Iron

Working Copper Ores at Spenceville

II. TECHNOLOGY AND CHEMISTRY-New Method of Detecting Dyes on Yarns and Tissues. By JULES JOFFRE.—Reagents.—Red colors.—Violet colors

Chevalet's Condenso-purifier for Gas.—2 figures.—Elevation and plan

Artificial Ivory

Creosote Impurities. By Prof P. W. BEDFORD

III. ELECTRICITY. ETC.—Sir William Thomson's Pile—2 figures

Siemens' Telemeter.—1 figure.—Siemens electric telemeter

Physics Without Apparatus.—Experiment in static electricity.— 1 figure

The Cascade Battery. By F. HIGGINS.—1 figure

Perfectly Lovely Philosophy

IV. ASTRONOMY, ETC.—The Comet as seen from the Pyramids near Cairo, Egypt.—1 figure

Sunlight and skylight at High Altitudes.—Influence of the atmosphere upon the solar spectrum.—Observations of Capt. Abney and Professor Langley.—2 figures

How to Establish a True Meridian

V. MINERALOGY.—The Mineralogical Localities in and Around New York City, and the Minerals Occurring Therein. By NELSON H. DAKTON. Part III.—Hoboken minerals.—Magnesite.—Dolomite. —Brucite.—Aragonite.—Serpentine.—Chromic iron—Datholite. —Pectolite.—Feldspar.—Copper mines, Arlington, N.J.-Green malachite.—Red oxide of copper.—Copper glance.—Erubescite

VI. ENTOMOLOGY.—The Buckeye Leaf Stem Borer

Defoliation of Oak Trees by Dryocampa senatoria in Perry County, Pa.

Efficacy of Chalcid Egg Parasites

On the Biology of Gonatopis Pilosus, Thoms

Species of Otiorhynchadae Injurious to Cultivated Plants

VII. ART, ARCHITECTURE, ETC.—Monteverde's Statue of Architecture. —Full page illustration, Lit Architectura. By JULI MONTEVERDE

Design for a Gardener's Cottage.—1 figure

VIII. HYGIENE AND MEDICINE.—Remedy for Sick Headache

IX. ORNITHOLOGY.—Sparrows in the United States.—Effects of acclimation, etc.

X. MISCELLANEOUS.—James Prescott Joule, with Portrait.—A sketch of the life and investigations of the discoverer of the mechanical equivalent of heat. By J. T. BOTTOMLEY

The Proposed Dutch International Colonial and General Export Exhibition.—1 figure.—Plan of the Amsterdam Exhibition

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THE COMET FROM THE PYRAMIDS, CAIRO

Some centuries ago, the appearance of so large a comet as is now interesting the astronomical world, almost contemporaneously with our victory in Egypt, would have been looked upon as an omen of great portent, and it is a curious coincidence that the first glimpse Sir Garnet Wolseley had of this erratic luminary was when standing, on the eventful morning of September 13, 1882, watch in hand, before the intrenchments of Tel-el-Kebir, waiting to give the word to advance. As may be seen in our sketch, the comet is seen in Egypt in all its magnificence, and the sight in the early morning from the pyramids (our sketch was taken at 4 A.M.) is described as unusually grand.—London Graphic.



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[NATURE.]



JAMES PRESCOTT JOULE.

James Prescott Joule was born at Salford, on Christmas Eve of the year 1818. His father and his grandfather before him were brewers, and the business, in due course, descended to Mr. Joule and his elder brother, and by them was carried on with success till it was sold, in 1854. Mr. Joule's grandfather came from Elton, in Derbyshire, settled near Manchester, where he founded the business, and died at the age of fifty-four, in 1799. His father, one of a numerous family, married a daughter of John Prescott of Wigan. They had five children, of whom James Prescott Joule was the second, and of whom three were sons—Benjamin, the eldest, James, and John—and two daughters—Alice and Mary. Mr. Joule's mother died in 1836 at the age of forty-eight; and his father, who was an invalid for many years before his death, died at the age of seventy-four, in the year 1858.

Young Joule was a delicate child, and was not sent to school. His early education was commenced by his mother's half sister, and was carried on at his father's house, Broomhill, Pendlebury, by tutors till he was about fifteen years of age. At fifteen he commenced working in the brewery, which, as his father's health declined, fell entirely into the hands of his brother Benjamin and himself.

Mr. Joule obtained his first instruction in physical science from Dalton, to whom his father sent the two brothers to learn chemistry. Dalton, one of the most distinguished chemists of any age or country, was then President of the Manchester Literary and Philosophical Society, and lived and received pupils in the rooms of the Society's house. Many of his most important memoirs were communicated to the Society, whose Transactions are likewise enriched by a large number of communications from his distinguished pupil. Dalton's instruction to the two young men commenced with arithmetic, algebra, and geometry. He then taught them natural philosophy out of Cavallo's text-book, and afterward, but only for a short time before his health gave way, in 1837, chemistry from his own "New System of Chemical Philosophy." "Profound, patient, intuitive," his teaching must have had great influence on his pupils. We find Mr. Joule early at work on the molecular constitution of gases, following in the footsteps of his illustrious master, whose own investigations on the constitution of mixed gases, and on the behavior of vapors and gases under heat, were among the most important of his day, and whose brilliant discovery of the atomic theory revolutionized the science of chemistry and placed him at the head of the philosophical chemists of Europe.



Under Dalton, Mr. Joule first became acquainted with physical apparatus; and the interest excited in his mind very soon began to produce fruit. Almost immediately he commenced experimenting on his own account. Obtaining a room in his father's house for the purpose, he began by constructing a cylinder electric machine in a very primitive way. A glass tube served for the cylinder; a poker hung up by silk threads, as in the very oldest forms of electric machine, was the prime conductor; and for a Leyden jar he went back to the old historical jar of Cunaeus, and used a bottle half filled with water, standing in an outer vessel, which contained water also.

Enlarging his stock of apparatus, chiefly by the work of his own hands, he soon entered the ranks as an investigator, and original papers followed each other in quick succession. The Royal Society list now contains, the titles of ninety-seven papers due to Joule, exclusive of over twenty very important papers detailing researches undertaken by him conjointly with Thomson, with Lyon Playfair, and with Scoresby.

Mr. Joule's first investigations were in the field of magnetism. In 1838, at the age of nineteen, he constructed an electro-magnetic engine, which he described in Sturgeon's "Annals of Electricity" for January of that year. In the same year, and in the three years following, he constructed other electro-magnetic machines and electro-magnets of novel forms; and experimenting with the new apparatus, he obtained results of great importance in the theory of electro-magnetism. In 1840 he discovered and determined the value of the limit to the magnetization communicable to soft iron by the electric current; showing for the case of an electro-magnet supporting weight, that when the exciting current is made stronger and stronger, the sustaining power tends to a certain definite limit, which, according to his estimate, amounts to about 140 lb. per square inch of either of the attracting surfaces. He investigated the relative values of solid iron cores for the electro-magnetic machine, as compared with bundles of iron wire; and, applying the principles which he had discovered, he proceeded to the construction of electro-magnets of much greater lifting power than any previously made, while he studied also the methods of modifying the distribution of the force in the magnetic field.

In commencing these investigations he was met at the very outset, as he tells us, with "the difficulty, if not impossibility, of understanding experiments and comparing them with one another, which arises in general from incomplete descriptions of apparatus, and from the arbitrary and vague numbers which are used to characterize electric currents. Such a practice," he says, "might be tolerated in the infancy of science; but in its present state of advancement greater precision and propriety are imperatively demanded. I have therefore determined," he continues, "for my own part to abandon my old quantity numbers, and to express my results on the basis of a unit which shall be at once scientific and convenient."

The discovery by Faraday of the law of electro-chemical equivalents had induced him to propose the voltameter as a measurer of electric currents, but the system proposed had not been used in the researches of any electrician, not excepting those of Faraday himself. Joule, realizing for the first time the importance of having a system of electric measurement which would make experimental results obtained at different times and under various circumstances comparable among themselves, and perceiving at the same time the advantages of a system of electric measurement dependent on, or at any rate comparable with, the chemical action producing the electric current, adopted as unit quantity of electricity the quantity required to decompose nine grains of water, 9 being the atomic weight of water, according to the chemical nomenclature then in use.

He had already made and described very important improvements in the construction of galvanometers, and he graduated his tangent galvanometer to correspond with the system of electric measurement he had adopted. The electric currents used in his experiments were thenceforth measured on the new system; and the numbers given in Joule's papers from 1840 downward are easily reducible to the modern absolute system of electric measurements, in the construction and general introduction of which he himself took so prominent a part. It was in 1840, also, that after experimenting on improvements in voltaic apparatus, he turned his attention to "the heat evolved by metallic conductors of electricity and in the cells of a battery during electrolysis." In this paper, and those following it in 1841 and 1842, he laid the foundation of a new province in physical science-electric and chemical thermodynamics-then totally unknown, but now wonderfully familiar, even to the roughest common sense practical electrician. With regard to the heat evolved by a metallic conductor carrying an electric current, he established what was already supposed to be the law, namely, that "the quantity of heat evolved by it [in a given time] is always proportional to the resistance which it presents, whatever may be the length, thickness, shape, or kind of the metallic conductor," while he obtained the law, then unknown, that the heat evolved is proportional to the square of the quantity of electricity passing in a given time. Corresponding laws were established for the heat evolved by the current passing in the electrolytic cell, and likewise for the heat developed in the cells of the battery itself.

In the year 1840 he was already speculating on the transformation of chemical energy into heat. In the paper last referred to and in a short abstract in the Proceedings of the Royal Society, December, 1840, he points out that the heat generated in a wire conveying a current of electricity is a part of the heat of chemical combination of the materials used in the voltaic cell, and that the remainder, not the whole heat of combination, is evolved within the cell in which the chemical action takes place. In papers given in 1841 and 1842, he pushes his investigations further, and shows that the sum of the heat produced in all parts of the circuit during voltaic action is proportional to the chemical action that goes on in the voltaic pile, and again, that the quantities of heat which are evolved by the combustion of equivalents of bodies are proportional to the intensities of their affinities for oxygen. Having proceeded thus far, he carried on the same train of reasoning and experiment till he was able to announce in January, 1843, that the magneto-electric machine enables us to convert mechanical power into heat. Most of his spare time in the early part of the year 1843 was devoted to making experiments necessary for the discovery of the laws of the development of heat by magneto-electricity, and for the definite determination of the mechanical value of heat.

At the meeting of the British Association at Cork, on August 21, 1843, he read his paper "On the Calorific Effects of Magneto-Electricity, and on the Mechanical Value of Heat." The paper gives an account of an admirable series of experiments, proving that heat is generated (not merely transferred from some source) by the magneto-electric machine. The investigation was pushed on for the purpose of finding whether a constant ratio exists between the heat generated and the mechanical power used in its production. As the result of one set of magneto-electric experiments, he finds 838 foot pounds to be the mechanical equivalent of the quantity of heat capable of increasing the temperature of one pound of water by one degree of Fahrenheit's scale. The paper is dated Broomhill, July, 1843, but a postscript, dated August, 1843, contains the following sentences:

"We shall be obliged to admit that Count Rumford was right in attributing the heat evolved by boring cannon to friction, and not (in any considerable degree) to any change in the capacity of the metal. I have lately proved experimentally that heat is evolved by the passage of water through narrow tubes. My apparatus consisted of a piston perforated by a number of small holes, working in a cylindrical glass jar containing about 7 lb. of water. I thus obtained one degree of heat per pound of water from a mechanical force capable of raising about 770 lb. to the height of one foot, a result which will be allowed to be very strongly confirmatory of our previous deductions. I shall lose no time in repeating and extending these experiments, being satisfied that the grand agents of nature are, by the Creator's fiat, indestructible, and that wherever mechanical force is expended, an exact equivalent of heat is always obtained."

This was the first determination of the dynamical equivalent of heat. Other naturalists and experimenters about the same time were attempting to compare the quantity of heat produced under certain circumstances with the quantity of work expended in producing it; and results and deductions (some of them very remarkable) were given by Seguin (1839), Mayer (1842), Colding (1843), founded partly on experiment, and partly on a kind of metaphysical reasoning. It was Joule, however, who first definitely proposed the problem of determining the relation between heat produced and work done in any mechanical action, and solved the problem directly.

It is not to be supposed that Joule's discovery and the results of his investigation met with immediate attention or with ready acquiescence. The problem occupied him almost continuously for many years; and in 1878 he gives in the Philosophical Transactions the results of a fresh determination, according to which the quantity of work required to be expended in order to raise the temperature of one pound of water weighed in vacuum from 60 deg. to 61 deg. Fahr., is 772.55 foot pounds of work at the sea level and in the latitude of Greenwich. His results of 1849 and 1878 agree in a striking manner with those obtained by Hirn and with those derived from an elaborate series of experiments carried out by Prof. Rowland, at the expense of the Government of the United States.

His experiments subsequent to 1843 on the dynamical equivalent of heat must be mentioned briefly. In that year his father removed from Pendlebury to Oak Field, Whalley Range, on the south side of Manchester, and built for his son a convenient laboratory near to the house. It was at this time that he felt the pressing need of accurate thermometers; and while Regnault was doing the same thing in France, Mr. Joule produced, with the assistance of Mr. Dancer, instrument maker, of Manchester, the first English thermometers possessing such accuracy as the mercury-in-glass thermometer is capable of. Some of them were forwarded to Prof. Graham and to Prof. Lyon Playfair; and the production of these instruments was in itself a most important contribution to scientific equipment.

As the direct experiment of friction of a fluid is dependent on no hypothesis, and appears to be wholly unexceptionable, it was used by Mr. Joule repeatedly in modified forms. The stirring of mercury, of oil, and of water with a paddle, which was turned by a falling weight, was compared, and solid friction, the friction of iron on iron under mercury, was tried; but the simple stirring of water seemed preferable to any, and was employed in all his later determinations.

In 1847 Mr. Joule was married to Amelia, daughter of Mr. John Grimes, Comptroller of Customs, Liverpool. His wife died early (1854), leaving him one son and one daughter.

The meeting of the British Association at Oxford, in this year, proved an interesting and important one. Here Joule read a fresh paper "On the Mechanical Equivalent of Heat." Of this meeting Sir William Thomson writes as follows to the author of this notice:

"I made Joule's acquaintance at the Oxford meeting, and it quickly ripened into a lifelong friendship.

"I heard his paper read in the section, and felt strongly impelled at first to rise and say that it must be wrong, because the true mechanical value of heat given, suppose in warm water, must, for small differences of temperature, be proportional to the square of its quantity. I knew from Carnot that this must be true (and it is true; only now I call it 'motivity,' to avoid clashing with Joule's 'mechanical value'). But as I listened on and on, I saw that (though Carnot had vitally important truth, not to be abandoned) Joule had certainly a great truth and a great discovery, and a most important measurement to bring forward. So, instead of rising, with my objection, to the meeting, I waited till it was over, and said my say to Joule himself, at the end of the meeting. This made my first introduction to him. After that I had a long talk over the whole matter at one of the conversaziones of the Association, and we became fast friends from thenceforward. However, he did not tell me he was to be married in a week or so; but about a fortnight later I was walking down from Chamounix to commence the tour of Mont Blanc, and whom should I meet walking up but Joule, with a long thermometer in his hand, and a carriage with a lady in it not far off. He told me he had been married since we had parted at Oxford! and he was going to try for elevation of temperature in waterfalls. We trysted to meet a few days later at Martigny, and look at the Cascade de Sallanches, to see if it might answer. We found it too much broken into spray. His young wife, as long as she lived, took complete interest in his scientific work, and both she and he showed me the greatest kindness during my visits to them in Manchester for our experiments on the thermal effects of fluid in motion, which we commenced a few years later"

"Joule's paper at the Oxford meeting made a great sensation. Faraday was there and was much struck with it, but did not enter fully into the new views. It was many years after that before any of the scientific chiefs began to give their adhesion. It was not long after, when Stokes told me he was inclined to be a Joulite."

"Miller, or Graham, or both, were for years quite incredulous as to Joule's results, because they all depended on fractions of a degree of temperature—sometimes very small fractions. His boldness in making such large conclusions from such very small observational effects is almost as noteworthy and admirable as his skill in extorting accuracy from them. I remember distinctly at the Royal Society, I think it was either Graham or Miller, saying simply he did not believe Joule, because he had nothing but hundredths of a degree to prove his case by."

The friendship formed between Joule and Thomson in 1847 grew rapidly. A voluminous correspondence was kept up between them, and several important researches were undertaken by the two friends in common. Their first joint research was on the thermal effects experienced by air rushing through small apertures The results of this investigation give for the first time an experimental basis for the hypothesis assumed without proof by Mayer as the foundation for an estimate of the numerical relation between quantities of heat and mechanical work, and they show that for permanent gases the hypothesis is very approximately true. Subsequently, Joule and Thomson undertook more comprehensive investigations on the thermal effects of fluids in motion, and on the heat acquired by bodies moving rapidly through the air. They found the heat generated by a body moving at one mile per second through the air sufficient to account for its ignition. The phenomena of "shooting stars" were explained by Mr. Joule in 1847 by the heat developed by bodies rushing into our atmosphere.

It is impossible within the limits to which this sketch is necessarily confined to speak in detail of the many researches undertaken by Mr. Joule on various physical subjects. Even of the most interesting of these a very brief notice must suffice for the present.

Molecular physics, as I have already remarked, early claimed his attention. Various papers on electrolysis of liquids, and on the constitution of gases, have been the result. A very interesting paper on "Heat and the Constitution of Elastic Fluids" was read before the Manchester Literary and Philosophical Society in 1848. In it he developed Daniel Bernoulli's explanation of air pressure by the impact of the molecules of the gas on the sides of the vessel which contains it, and from very simple considerations he calculated the average velocity of the particles requisite to produce ordinary atmospheric pressure at different temperatures. The average velocity of the particles of hydrogen at 32 deg. F. he found to be 6,055 feet per second, the velocities at various temperatures being proportional to the square roots of the numbers which express those temperatures on the absolute thermodynamic scale.

His contribution to the theory of the velocity of sound in air was likewise of great importance, and is distinguished alike for the acuteness of his explanations of the existing causes of error in the work of previous experimenters, and for the accuracy, so far as was required for the purpose in hand, of his own experiments. His determination of the specific heat of air, pressure constant, and the specific heat of air, volume constant, furnished the data necessary for making Laplace's theoretical velocity agree with the velocity of sound experimentally determined. On the other hand, he was able to account for most puzzling discrepancies, which appeared in attempted direct determinations of the differences between the two specific heats by careful experimenters. He pointed out that in experiments in which air was allowed to rush violently or explode into a vacuum, there was a source of loss of energy that no one had taken account of, namely, in the sound produced by the explosion. Hence in the most careful experiments, where the vacuum was made as perfect as possible, and the explosion correspondingly the more violent, the results were actually the worst. With his explanations, the theory of the subject was rendered quite complete.

Space fails, or I should mention in detail Mr. Joule's experiments on magnetism and electro-magnets, referred to at the commencement of this sketch. He discovered the now celebrated change of dimensions produced by the magnetization of soft iron by the current. The peculiar noise which accompanies the magnetization of an iron bar by the current, sometimes called the "magnetic tick," was thus explained.

Mr. Joule's improvements in galvanometers have already been incidentally mentioned, and the construction by him of accurate thermometers has been referred to. It should never be forgotten that he first used small enough needles in tangent galvanometers to practically annul error from want of uniformity of the magnetic field. Of other improvements and additions to philosophical instruments may be mentioned a thermometer, unaffected by radiation, for measuring the temperature of the atmosphere, an improved barometer, a mercurial vacuum pump, one of the very first of the species which is now doing such valuable work, not only in scientific laboratories, but in the manufacture of incandescent electric lamps, and an apparatus for determining the earth's horizontal magnetic force in absolute measure.

Here this imperfect sketch must close. My limits are already passed. Mr. Joule has never been in any sense a public man; and, of those who know his name as that of the discoverer who has given the experimental basis for the grandest generalization in the whole of physical science, very few have ever seen his face. Of his private character this is scarcely the place to speak. Mr. Joule is still among us. May he long be spared to work for that cause to which he has given his life with heart-whole devotion that has never been excelled.

In June, 1878, he received a letter from the Earl of Beaconsfield announcing to him that Her Majesty the Queen had been pleased to grant him a pension of L200 per annum. This recognition of his labors by his country was a subject of much gratification to Mr. Joule.

Mr. Joule received the Gold Royal Medal of the Royal Society in 1852, the Copley Gold Medal of the Royal Society in 1870, and the Albert Medal of the Society of Arts from the hand of the Prince of Wales in 1880.

J. T. BOTTOMLEY.

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THE NEW YORK CANALS.

The recent adoption of the constitutional amendment abolishing tolls on the canals of New York State has revived interest in these water ways. The overwhelming majority by which the measure was passed shows, says the Glassware Reporter, that the people are willing to bear the cost of their management by defraying from the public treasury all expenses incident to their operation. That the abolition of the toll system will be a great gain to the State seems to be admitted by nearly everybody, and the measure met with but little opposition except from the railroad corporations and their supporters.

At as early a date as the close of the Revolutionary War, Mr. Morris had suggested the union of the great lakes with the Hudson River, and in 1812 he again advocated it. De Witt Clinton, of New York, one of the most, valuable men of his day, took up the idea, and brought the leading men of his State to lend him their support in pushing it. To dig a canal all the way from Albany to Lake Erie was a pretty formidable undertaking; the State of New York accordingly invited the Federal government to assist in the enterprise.

The canal was as desirable on national grounds as on any other, but the proposition met with a rebuff, and the Empire State then resolved to build the canal herself. Surveyors were sent out to locate a line for it, and on July 4, 1817, ground was broken for the canal by De Witt Clinton, who was then Governor of the State.

The main line, from Albany, on the Hudson, to Buffalo, on Lake Erie, measures 363 miles in length, and cost $7,143,789. The Champlain, Oswego, Chemung, Cayuga, and Crooked Lake canals, and some others, join the main line, and, including these branch lines, it measures 543 miles in length, and cost upward of $11,500,000. This canal was originally 40 feet in breadth at the water line, 28 feet at the bottom, and 4 feet in depth. Its dimensions proved too small for the extensive trade which it had to support, and the depth of water was increased to 7 feet, and the extreme breadth of the canal to 60 feet. There are 84 locks on the main line. These locks, originally 90 feet in length and 15 in breadth, and with an average lift of 8 feet 2 inches, have since been much enlarged. The total rise and fall is 692 feet. The towpath is elevated 4 feet above the level of the water, and is 10 feet in breadth. At Lockport the canal descends 60 feet by means of 5 locks excavated in solid rock, and afterward proceeds on a uniform level for a distance of 63 miles to the Genesee River, over which it is carried on an aqueduct having 9 arches of 50 feet span each. Eight and a half miles from this point it passes over the Cayuga marsh, on an embankment 2 miles in length, and in some places 70 feet in height. At Syracuse, the "long level" commences, which extends for a distance of 691/2 miles to Frankfort, without an intervening lock. After leaving Frankfort, the canal crosses the river Mohawk, first by an aqueduct 748 feet in length, supported on 16 piers, elevated 25 feet above the surface of the river, and afterward by another aqueduct 1,188 feet in length, and emerges into the Hudson at Albany.

This great work was finished in 1825, and its completion was the occasion of great public rejoicing. The same year that the Erie Canal was begun, ground was broken for a canal from Lake Champlain to the Hudson, sixty-three miles in length. This work was completed in 1823.

The construction of these two water ways was attended with the most interesting consequences. Even before they were completed their value had become clearly apparent. Boats were placed upon the Erie Canal as fast as the different levels were ready for use, and set to work in active transportation. They were small affairs compared with those of the present day, being about 50 or 60 tons burden, the modern canal boat being 180 or 200 tons. Small as they were, they reduced the cost of transportation immediately to one-tenth what it had been before. A ton of freight by land from Buffalo to Albany cost at that time $100. When the canal was open its entire length, the cost of freight fell from fifteen to twenty-five dollars a ton, according to the class of article carried; and the time of transit from 20 to 8 days, Wheat at that time was worth only $33 a ton in western New York, and it did not pay to send it by land to New York. When sent to market at all, it was floated down the Susquehanna to Baltimore, as being the cheapest and best market. The canal changed that. It now became possible to send to market a wide variety of agricultural produce—fruit, grain, vegetables, etc.—which, before the canal was built, either had no value at all, or which could be disposed of to no good advantage. It is claimed by the original promoters of the Erie Canal, who lived to see its beneficial effects experienced by the people of the country, that their work, costing less than $8.000,000 and paying its whole cost of construction in a very few years, added $100,000,000 to the value of the farms of New York by opening up good and ready markets for their products. The canal had another result. It made New York city the commercial metropolis of the country. An old letter, written by a resident of Newport, R. I., in that age, has lately been discovered, which speaks of New York city, and says: "If we do not look out, New York will get ahead of us." Newport was then one of the principal seaports of the country; it had once been the first. New York city certainly did "get ahead of us" after the Erie Canal was built. It got ahead of every other commercial city on the coast. Freight, which had previously gone overland from Ohio and the West to Pittsburg, and thence to Philadelphia, costing $120 a ton between the two cities named, now went to New York by way of the Hudson River and the Erie Canal and the lakes. Manufactures and groceries returned to the West by the same route, and New York became a flourishing and growing emporium immediately. The Erie Canal was enlarged in 1835, so as to permit the passage of boats of 100 tons burden, and the result was a still further reduction of the cost of freighting, expansion of traffic, and an increase of the general benefits conferred by the canal. The Champlain Canal had an effect upon the farms and towns lying along Lake Champlain, in Vermont and New York, kindred in character to that above described in respect to the Erie Canal. It brought into the market lands and produce which before had been worthless, and was a great blessing to all concerned.

There can be no doubt that the building of the Erie Canal was the wisest and most far-seeing enterprise of the age. It has left a permanent and indelible mark upon the face of the republic of the United States in the great communities it has directly assisted to build up at the West, and in the populous metropolis it created at the mouth of the Hudson River. None of the canals which have been built to compete with it have yet succeeded in regaining for their States what was lost to them when the Erie Canal went into operation. This water route is still the most important artificial one of its class in the country, and is only equaled by the Welland Canal in Canada, which is its closest rival. Now that it is free, it will retain its position as the most popular water route to the sea from the great West. The Mississippi River will divert from it all the trade flowing to South America and Mexico; but for the northwest it will be the chief water highway to the ocean.

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COTTRAU'S LOCOMOTIVE FOR ASCENDING STEEP GRADES.

We borrow, from our contemporary La Nature, the annexed figure, illustrating an ingenious type of locomotive designed for equally efficient use on both level surfaces and heavy grades.



As well known, all the engines employed on level roads are provided with large driving wheels, which, although they have a comparatively feeble tractive power, afford a high speed, while, on the contrary, those that are used for ascending heavy grades have small wheels that move slowly, but possess, as an offset, a tractive power that enables them to overcome the resistances of gravity.

M. Cottrau's engine possesses the qualities of both these types, since it is provided with wheels of large and small diameter, that may be used at will. These two sets of wheels, as may be seen from the figure, are arranged on the same driving axle. The large wheels are held apart the width of the ordinary track, while the small wheels are placed internally, or as in the case represented in the figure, externally. These two sets of wheels, being fixed solidly to the same axle, revolve together.

On level surfaces the engine rests on the large wheels, which revolve in contact with the rails of the ordinary track, and it then runs with great speed, while the auxiliary wheels revolve to no purpose. On reaching an ascent, on the contrary, the engine meets with an elevated track external or internal to the ordinary one, and which engages with the auxiliary wheels. The large wheels are then lifted off the ordinary track and revolve to no purpose. In both cases, the engine is placed under conditions as advantageous as are those that are built especially for the two types of roads. The idea appears to be a very ingenious one, and can certainly be carried out without disturbing the working of the locomotive. In fact, the same number of piston strokes per minute may be preserved in the two modes of running, so as to reduce the speed in ascending, in proportion to the diameters of the wheels. There will thus occur the same consumption of steam. On another hand, there is nothing to prevent the boiler from keeping up the same production of steam, for it has been ascertained by experience, on the majority of railways, that the speed of running has no influence on vaporization, and that the same figures may be allowed for passenger as for freight locomotives.

The difficulties in the way of construction that will be met with in the engine under consideration will be connected with the placing of the double wheels, which will reduce the already limited space at one's disposal, and with the necessity that there will be of strengthening all the parts of the mechanism that are to be submitted to strain.

The installation of the auxiliary track will also prove a peculiarly delicate matter; and, to prevent accidents, some means will have to be devised that will permit the auxiliary wheels to engage with this track very gradually. Still, these difficulties are perhaps not insurmountable, and if M. Cottrau's ingenious arrangement meets with final success in practice, it will find numerous applications.

* * * * *



BACHMANN'S STEAM DRIER.

The apparatus shown in the annexed cuts is capable of effecting a certain amount of saving in the fuel of a generator, and of securing a normal operation in a steam engine. If occasion does not occur to blow off the motive cylinder frequently, the water that is carried over mechanically by the steam, or that is produced through condensation in the pipes, accumulates therein and leaks through the joints of the cocks and valves. This is one of the causes that diminish the performance of the motor.



The steam drier under consideration has been devised by Mr. Bachmann for the purpose of doing away with such inconveniences. When applied to apparatus employed in heating, for cooking, for work in a vacuum, it may be affixed to the pipe at the very place where the steam is utilized, so as to draw off all the water from the mixture.

As shown by the arrows in Fig 1, the steam enters through the orifice, D, along with the water that it carries, gives up the latter at P, and is completely dried at the exit, R. The partition, g, is so arranged as to diminish the section of the steam pipe, in order to increase the effect of the gravity that brings about the separation of the mixture. The water that falls into the space, P, is exhausted either by means of a discharge cock (Fig. 1), which gives passage to the liquid only, or by the aid of an automatic purge-cock (Figs. 2 and 3), the locating of which varies with the system employed. This arrangement is preferable to the other, since it permits of expelling the water deposited in the receptacle, P, without necessitating any attention on the part of the engine-man.

* * * * *



H.S. PARMELEE'S PATENT AUTOMATIC SPRINKLER.

The inventor says: "The automatic sprinkler is a device for automatically extinguishing fires through the release of water by means of the heat of the fire, the water escaping in a shower, which is thrown in all directions to a distance of from six to eight feet. The sprinkler is a light brass rose, about 11/2 inches diameter and less than two inches high entire, the distributer being a revolving head fitted loosely to the body of the fixed portion, which is made to screw into a half inch tube connection. The revolution of the distributer is effected by the resistance the water meets in escaping through slots cut at an angle in the head. The distribution of water has been found to be the most perfect from this arrangement. Now, this distributing head is covered over with a brass cap, which is soldered to the base beneath with an alloy which melts at from 155 to 160 degrees. No water can escape until the cap is removed. The heat of an insignificant fire is sufficient to effect this, and we have the practical prevention of any serious damage or loss through the multiplication of the sprinkler.



The annexed engravings represent the sprinkler at exact size for one-half inch connection. Fig. 1 shows a section with the cap covering over the sprinkler, and soldered on to the base. Fig. 2 shows the sprinkler with the cap off, which, of course, leaves the water free to run from the holes in fine spray in all directions. Fig. 1 shows the base hollowed out so as to allow the heat to circulate in between the pipe and the base of the sprinkler, thus allowing the heat to operate on the inside as well as on the outside of the sprinkler; thus, in case of fire, it is very quickly heated through sufficiently to melt the fusible solder. These sprinklers are all tested at 500 lb., consequently they can never leak, and cannot possibly be opened, except by heat, by any one. As the entire sprinkler is covered by a heavy brass cap, soldered on, it cannot by any means be injured, nor can the openings in the revolving head ever become filled with dust.



It is so simple as to be easily understood by any one. As soon as the sprinkler becomes heated to 155 degrees, the cap will become unsoldered, and will then immediately be blown entirely off by the force of the water in the pipes and sprinkler. These caps cannot remain on after the fusible metal melts, if there is the least force of water. A man's breath is sufficient to blow them off.

The arrangement commences with one or more main supply pipes, either fed from a city water pipe or from a tank, as the situation will admit. If desired, the tank need only be of sufficient size to feed a few sprinklers for a short time, and then dependence must be placed upon a pump for a further supply of water, if necessary. The tank, however small, will insure the automatic and prompt working of the sprinklers and alarm, and by the time the tank shall become empty the pumps can be got at work. It is most desirable, however, in all cases to have an abundant water supply without resorting to pumps, if it is possible.

In the main supply pipe or pipes is placed our patent alarm valve, which, as soon as there is any motion of the water in the pipe, opens, and moves a lever, which, by connecting with a steam whistle valve by means of a wire, will blow the whistle and will continue to do so until either the steam or the water is stopped. Tins constitutes the alarm, and is positive in its motion. No water can possibly flow from the line of pipes without opening this valve and blowing the whistle. We also put in an automatic alarm bell when desired.

From the main pipe other pipes are run, generally lengthways of the building, ten feet from each side and twenty feet apart. At every ten feet on these pipes we place five feet of three-quarter inch pipe, reaching each side, at the end of which is placed the sprinkler in an elbow pointing toward the ceiling. This arrangement is as we place them in all cotton and woolen mills, but may be varied to suit different styles of buildings.

The sprinkler is made of brass, and has a revolving head, with four slots, from which the water flies in a very fine and dense spray on everything, and filling the air very completely for a radius of seven or eight feet all around; thus rendering the existence of any fire in that space perfectly impossible; and as the sprinklers are only placed ten feet apart, and a fire cannot start at a greater distance than from five to six feet from one or more of them, it is assured that all parts of a building are fully protected.

Over each one of these sprinklers is placed a brass cap, which fits closely over and passes below the base, where it is soldered on with a fusible metal that melts as soon as it is heated to 155 degrees.

As soon as a fire starts in any part of a building, heat will be generated and immediately rise toward the ceiling, and the sprinkler nearest the fire will become heated in a very few moments to the required 155 degrees, when the cap will become loosened and will be forced off by the power of the water. The water will then be spread in fine spray on the ceiling over the fire, also directly on the fire and all around for a diameter of from fourteen to eighteen feet. This spray has been fully tried, and it is found to be entirely sufficient to extinguish any fire within its reach which can be made of any ordinary materials.

As soon as the cap on any sprinkler becomes loosened by the heat of a fire and is forced off, a current of water is produced in the main pipe where the alarm valve is placed, and as the passage through it is dosed, the water cannot pass without opening the valve and thus moving the lever to which the steam whistle valve is attached; by this motion the whistle valve is opened, and the whistle will blow until it is stopped by some one."

* * * * *



INSTRUMENT FOR DRAWING CONVERGING STRAIGHT LINES.

[Footnote: Paper by Prof. Fr. Smigaglia, read at the reunion of the Engineers and Architects of Rome.]

1. LET A and B be two fixed points and A C and C B two straight lines converging at C and moving in their plane so as to always remain based on this point (Fig. 1). The geometrical place of the positions occupied by C is the circumference of the circle which passes through the three points A, B, and C. Now let C F be a straight line passing through C. On prolonging it, it will meet the circumference A C B I at a point I. If the system of three converging—lines takes a new position A C' F B, it is evident F' B' prolonged will pass through I, because the angles [alpha] and [beta] are invariable for any position whatever of the system.



2. In the particular case in which [alpha] = [beta] (Fig. 2), the point I is found at the extremity of the diameter, and, consequently, for a given distance A B, or for a given length C D, such point will be at its maximum distance from C.



3. This granted, it is easy to construct an instrument suitable for drawing converging lines which shall prove useful to all those who have to do with practical perspective. For this purpose it is only necessary to take three rulers united at C (Fig. 3), to rest the two A C and C B against two points or needles A and B, and to draw the lines with the ruler C F, in placing the system (Sec. 1) in all positions possible. The three rulers may be inclined in any way whatever toward each other, but (Sec. 2) it is preferable to take the case where [alpha] = [beta].



4. Let us suppose that the instrument passes from the position I to position III (Fig. 4). Then the ruler C A will come to occupy the position B A, from the fact that the instrument, continuing to move in the same direction, will roll around the point B. It is well, then, to manage so that the system shall have another point of support. For that reason I prolong C B, take B C' = B C, draw C' I, and describe the circumference—the geometrical place of the points C'. I take C' D = C' B and obtain at D the position of the fixed point at which the needle is inserted. In Fig. 4 are represented different positions of the instrument; and it may be seen that all the points C C', and the centers O O', are found upon the circumferences that have their center at I.



5. The manipulation and use of the instrument are of the simplest character. Being given any two straight converging lines whatever, [alpha] [beta] and [gamma] [delta] (Fig. 5), in order to trace all the others I insert a needle at A and arrange the instrument as seen at S. I draw A B and A B', and from there carry it to S' in such a way that the ruler being on [gamma] [delta], one of the resting rulers passes through A. I draw the line C B which meets A B at the point B, the position sought for the second needle. In order to draw the straight lines which are under [alpha] [beta], it is only necessary to hold the needle A in place and to fix one at B', making A B' = A B. In this case S" indicates one of the positions of the instrument.



6. The point A was chosen arbitrarily, but it is evident that that of the needles depends on its distance from the point of convergence. Thus, on taking A' instead of A in the case of Fig. 3, they approach, while the contrary happens on choosing the point A". It is clear that the different positions that a needle A may take are found on a straight line which runs to the point of meeting.

7. If the instrument were jointed or hinged at C, that is to say, so that we could at will modify the angle of the resting ruler, we might make the position of the needles depend on such angle, and conversely.

8. Being given the length C I (Fig. 6), to establish the position of the needles so that all the lines outside of the sheet shall converge at I. To do this, it is well to determine C D, and then to draw the straight line A D B perpendicular to C I, so as to have at A and B the points at which the needles must be placed.



Then

_ _ _ AD squared CD squared CD x DI = AD squared. CD = —— = ————- tang squared[alpha], DI CI - CD

[TEX: CD imes DI = overline{AD^2}. CD = frac{overline{AD^2}}{DI} = frac{overline{CD^2}}{CI-CD} an^2 alpha]

whence

CI CD = ————————— or CD = CI cos squared[alpha]. (1) I + tang squared[alpha]

[TEX: CD = frac{CI}{I + an^2 alpha} ext{or} CD = CI cos^2 alpha.]

9. If the instrument is jointed, the absolute values being

___ / AD = / CD(CI - CD) , (2) /

[TEX: AD = sqrt{CD(CI - CD)}]

it suffices to take for CD a suitable value and to calculate AD.

If, for example, the value of C D is represented by C D', the instrument takes the position A' C B', and the needles will be inserted at A' and B' on the line A' D' B', which is perpendicular to C I.

10. If the position of the instrument, and consequently that of the needles, has been established, and we wish to know the distance C I, we will have

CD CI = —————— ; (3) cos squared[alpha]

[TEX: CI = frac{CD}{cos^2 alpha}]

or, again,

_ AC squared CI = ——- (4) CD'

[TEX: CI = frac{overline{AC^2}}{CD'}]

11. In order to avoid all calculation, we may proceed thus: If I wish to arrange the instrument so that C I represents a given quantity (Sec. 8), I take (Fig. 7) the length Ci = CI/n, where n is any entire number whatever.



In other terms, Ci is the reduction to the scale of CI.

I describe the circumference C b i a, and arrange the instrument as seen in the figure, and measure the length C b.

It is visible that

C i 1 C b C d ——- = —- = ——- = ———; then C B = n.C b (5) C I n C B C D

CD = n.C d; (6)

and, consequently, the position of the needles which are found at A and B are determined.

12. The question treated in Sec. 10, then, is simply solved. In fact, on describing the circumference C b i a with any radius whatever, I shall have

C B n = ——-; (7) c b

and, consequently,

C I = n.C i (8)

13. As may be seen, the instrument composed of three firmly united rulers is the simplest of all and easy to use. Any one can construct it for himself with a piece of cardboard, and give the angle 2 [alpha] the value that he thinks most suitable for each application. The greater 2 [alpha] is, the shorter is the distance at which we should put the needles for a given point of meeting.

14 The jointed instrument may be constructed as shown in Figs 8, 9, and 10. The three pieces, A. B, and C, united by a pivot, O, in which there is a small hole, are of brass or other metal. Rulers may be easily procured of any length whatever. The instrument is Y-shaped. In the particular case in which [alpha] = 180 deg. it becomes T-shaped, and serves to draw parallel lines.



15. The instrument may be used likewise, as we have seen, to draw arcs of circles of the diameter C I or of the radius A O = r, whose center o falls outside the paper. The pencil will be rested on C. We may operate as follows (Fig. 2): Being given the direction of the radii A O and B O, or, what amounts to the same thing, the tangents to the curve at the given points, A and B to be united, we draw the line A D and raise at its center the perpendicular D C, which, prolonged, passes necessarily through the center. It is necessary to calculate the length C D.

We shall have

_ _ _ CD (2r - CD) = AD squared.CD squared - 2r.CD + AD squared = o.

[TEX: CD (2r - CD) = overline{AD^2}.overline{CD^2} - 2r.CD + overline{AD^2} = o.]

__ / _ CD = r +- / r squared - AD squared . /

[TEX: CD = r +- sqrt{r^2 - overline{AD^2}}.]

It is evident that the lower sign alone suits our case, for d < r; consequently,

__ / _ CD = r - / r squared - AD squared . (9) /

[TEX: CD = r - sqrt{r^2 - overline{AD^2}}.]

Having obtained C, we put the instrument in the direction A B C. Then each point of C F describes a circumference of the same center o.

16. If the distance of the points A and B were too great, then it would be easy to determine a series of points belonging to the arc of circumference sought (Fig. 4).

Being given C, the direction C I, and C I = R, on C I I lay off C E = d, draw A E B perpendicularly, and calculate C A or A E. I shall have

_ d = (R - d) = AE squared;

[TEX: d = (R - d) = overline{AE^2};]

or, as absolute value,

/ A E = / d (R - d) . (10) /

[TEX: AE = sqrt{d (R-d)}]

The instrument being arranged according to A C B, I prolong C B and take B C' = B C, when C' will be one of the points sought. It will be readily understood how, by repeating the above operations, but by varying the value of d, we obtain the other intermediate points, and how we may continue the operation to the right of C' with the process pointed out.

17. If the three rulers were three arcs of a large circle of a sphere, the instrument might serve for drawing the meridians on such sphere.

18. If we imagine, instead of three axes placed in one plane and converging at one point, a system of four axes also converging in one point, but situated in any manner whatever in space, and if we rest three of them against three fixed points, we shall be able to solve in space problems analogous to those that have just been solved in a plane. If we had, for example, to draw a spherical vault whose center was inaccessible, we might adopt the same method.—Le Genie Civil.

* * * * *



FEED-WATER HEATER AND PURIFIER.

[Footnote: A paper read before the Franklin Institute.]

By GEORGE S. STRONG.

In order to properly understand the requirements of an effective feed-water purifier, it will be necessary to understand something of the character of the impurities of natural waters used for feeding boilers, and of the manner in which they become troublesome in causing incrustation or scale, as it is commonly called, in steam boilers. All natural waters are known to contain more or less mineral matter, partly held in solution and partly in mechanical suspension. These mineral impurities are derived by contact of the water with the earth's surface, and by percolation through its soil and rocks. The substances taken up in solution by this process consist chiefly of the carbonates and sulphates of lime and magnesia, and the chloride of sodium. The materials carried in mechanical suspension are clay, sand, and vegetable matter. There are many other saline ingredients in various natural waters, but they exist in such minute quantities, and are generally so very soluble, that their presence may safely be ignored in treating of the utility of boiler waters.

Of the above named salts, the carbonates of lime and magnesia are soluble only when the water contains free carbonic acid.

Our American rivers contain from 2 to 6 grains of saline matter to the gallon in solution, and a varying quantity—generally exceeding 10 grains to the gallon—in mechanical suspension. The waters of wells and springs hold a smaller quantity in suspension, but generally carry a larger percentage of dissolved salts in solution, varying from 10 to 650 grains to the gallon.

When waters containing the carbonates of lime and magnesia in solution are boiled, the carbonic acid is driven off, and the salts, deprived of their solvent, are rapidly precipitated in fine crystalline particles, which adhere tenaciously to whatever surface they fall upon. With respect to the sulphate of lime, the case is different. It is at best only sparingly soluble in water, one part (by weight) of the salt requiring nearly 500 parts of water to dissolve it. As the water evaporates in the boiler, however, a point is soon reached where supersaturation occurs, as the water freshly fed into it constantly brings fresh accessions of the salt; and when this point is reached, the sulphate of lime is precipitated in the same form and with the same tenaciously adherent quality as the carbonates. There is, however, a peculiar property possessed by this salt which facilitates its precipitation, namely, that its solubility in water diminishes as the temperature rises. This fact is of special interest, since, if properly taken advantage of, it is possible to effect its almost complete removal from the feed-water of boilers,

There is little difference in the solubility of the sulphate of lime until the temperature has risen somewhat above 212 deg. Fahr., when it rapidly diminishes, and finally, at nearly 300 deg., all of this salt, held in solution at lower temperatures, will be precipitated when the temperature has risen to that point. The following table[1] represents the solubility of sulphate of lime in sea water at different temperatures:

Temperature. Percentage Sulph. Fahr. Lime held in Solution. 217 deg. 0.500 219 deg. 0.477 221 deg. 0.432 227 deg. 0.395 232 deg. 0.355 236 deg. 0.310 240 deg. 0.267 245 deg. 0.226 250 deg. 0.183 255 deg. 0.140 261 deg. 0.097 266 deg. 0.060 271 deg. 0.023 290 deg. 0.000

[Footnote 1: Vide Burgh, "Modern Marine Engineering," page 176 et seq. M. Couste, Annales des Mines V 69. Recherches sur Vincrustation des Chaudieres a vapour. Mr. Hugh Lee Pattison, of Newcastle-on-Tyne, at the meeting of the Institute of Mechanical Engineers of Great Britain, in August, 1880, remarked on this subject that "The solubility of sulphate of lime in water diminishes as the temperature rises. At ordinary temperatures pure water dissolves about 150 grains of sulphate of lime per gallon; but at a temperature of 250 deg. Fahr., at which the pressure of steam is equal to about 2 atmospheres, only about 40 grains per gallon are held in solution. At a pressure of 3 atmospheres, and temperature of 302 deg. Fahr., it is practically insoluble. The point of maximum solubility is about 95 deg. Fahr. The presence of magnesium chloride, or of calcium chloride, in water, diminishes its power of dissolving sulphate of lime, while the presence of sodium chloride increases that power. As an instance of the latter fact, we find a boiler works much cleaner which is fed alternately with fresh water and with brackish water pumped from the Tyne when the tide is high than one which is fed with fresh water constantly."]

These figures hold substantially for fresh as well as for sea water, for the sulphate of lime becomes wholly insoluble in sea water, or in soft water, at temperatures comprised between 280 deg. and 300 deg. Fahr.

It appears from this that it is simply necessary to heat water up to a temperature of 250 deg. in order to effect the precipitation of four fifths of the sulphate of lime it may have contained, or to the temperature of 290 deg. in order to precipitate it entirely. The bearing of these facts on the purification of feed-waters will appear further on. The explanation offered to account for the gradually increasing insolubility of sulphate of lime on heating, is, that the hydrate, in which condition it exists in solution, is partially decomposed, anhydrous calcic sulphate being formed, the dehydration becoming more and more complete as the temperature rises. Sulphate of magnesia, chloride of sodium (common salt), and all the other more soluble salts contained in natural waters are likewise precipitated by the process of supersaturation, but owing to their extreme solubility their precipitation will never be effected in boilers; all mechanically suspended matter tends naturally to subside.

Where water containing such mineral and suspended matter is fed to a steam boiler, there results a combined deposit, of which the carbonate of lime usually forms the greater part, and which remains more or less firmly adherent to the inner surfaces of the boiler, undisturbed by the force of the boiling currents. Gradually accumulating, it becomes harder and thicker, and, if permitted to accumulate, may at length attain such thickness as to prevent the proper heating of the water by any fire that may be maintained in the furnace. Dr. Joseph G. Rogers, who has made boiler waters and incrustations a subject of careful study, declares that the high heats necessary to heat water through thick scale will sometimes actually convert the scale into a species of glass, by combining the sand, mechanically separated, with the alkaline salts. The same authority has carefully estimated the non-conducting properties of such boiler incrustations. On this point he remarks that the evil effects of the scale are due to the fact that it is relatively a nonconductor of heat. As compared with iron, its conducting power is as 1 to 371/2, consequently more fuel is required to heat water in an incrusted boiler than in the same boiler if clean. Rogers estimates that a scale 1-16th of an inch thick will require the extra expenditure of 15 per cent. more fuel, and this ratio increases as the scale grows thicker. Thus, when it is one-quarter of an inch thick, 60 per cent. more fuel is needed; one-half inch, 112 per cent. more fuel, and so on.

Rogers very forcibly shows the evil consequences to the boiler from the excessive heating required to raise steam in a badly incrusted boiler, by the following illustration: To raise steam to a pressure of 90 pounds the water must be heated to about 320 deg. Fahr. In a clean boiler of one-quarter inch iron this may be done by heating the external surface of the shell to about 325 deg. Fahr. If, now, one-half an inch of scale intervenes between the boiler shell and the water, such is its quality of resisting the passage of heat that it will be necessary to heat the fire surface to about 700 deg., almost to a low red heat, to effect the same result. Now, the higher the temperature at which iron is kept the more rapidly it oxidizes, and at any heat above 600 deg. it very soon becomes granular and brittle, and is liable to bulge, crack, or otherwise give way to the internal pressure. This condition predisposes the boiler to explosion and makes expensive repairs necessary. The presence of such scale, also, renders more difficult the raising, maintaining, and lowering of steam.

The nature of incrustation and the evils resulting therefrom having been stated, it now remains to consider the methods that have been devised to overcome them. These methods naturally resolve themselves into two kinds, chemical and mechanical. The chemical method has two modifications; in one the design is to purify the water in large tanks or reservoirs, by the addition of certain substances which shall precipitate all the scale-forming ingredients before the water is fed into the boiler; in the other the chemical agent is fed into the boiler from time to time, and the object is to effect the precipitation of the saline matter in such a manner that it will not form solid masses of adherent scale. Where chemical methods of purification are resorted to, the latter plan is generally followed as being the least troublesome. Of the many substances used for this purpose, however, some are measurably successful; the majority of them are unsatisfactory or objectionable.

The mechanical methods are also very various. Picking, scraping, cleaning, etc., are very generally resorted to, but the scale is so tenacious that this only partially succeeds, and, as it necessitates stoppage of work, it is wasteful. In addition to this plan, a great variety of mechanical contrivances for heating and purifying the feed-water, by separating and intercepting the saline matter on its passage through the apparatus, have been devised. Many of these are of great utility and have come into very general use. In the Western States especially, where the water in most localities is heavily charged with lime, these mechanical purifiers have become quite indispensable wherever steam users are alive to the necessity of generating steam with economy.

Most of these appliances, however, only partly fulfill their intended purposes. They consist essentially of a chamber through which the feed-water is passed, and in which it is heated almost to the boiling point by exhaust steam from the engine. According to the temperature to which the water is heated in this chamber, and the length of time required for its passage through the chamber, the carbonates are more or less completely precipitated, as likewise the matter held in mechanical suspension. The precipitated matter subsides on shelves or elsewhere in the chamber, from which it is removed from time to time. The sulphate of lime, however, and the other soluble salts, and in some cases also a portion of the carbonates that were not precipitated during the brief time of passage through the heater, are passed on into the boiler.

Appreciating this insufficiency of existing feed-water purifiers to effectually remove these dangerous saline impurities, the writer in designing the feed-water heater now to be described paid special attention to the separation of all matters, soluble and insoluble; and he has succeeded in passing the water to the boilers quite free from any substance which would cause scaling or coherent deposit. His attention was called more particularly to the necessity of extreme care in this respect, through the great annoyance suffered by steam users in the Central and Western States, where the water is heavily charged with lime. Very simple and even primitive boilers are here used; the most necessary consideration being handiness in cleaning, and not the highest evaporative efficiency. These boilers are therefore very wasteful, only evaporating, when covered with lime scale, from two to three pounds of water with one pound of the best coal, and requiring cleansing once a week at the very least. The writer's interest being aroused, he determined, if possible, to remedy these inconveniences, and accordingly he made a careful study of the subject, and examined all the heaters then in the market. He found them all, without exception, insufficient to free the feed-water from the most dangerous of impurities, namely, the sulphate and the carbonate of lime.

Taking the foregoing facts, well known to chemists and engineers, as the basis of his operations, the writer perceived that all substances likely to give trouble by deposition would be precipitated at a temperature of about 250 deg. F.

His plan was, therefore, to make a feed-water heater in which the water could be raised to that temperature before entering the boiler. Now, by using the heat from the exhaust steam the water may be raised to between 208 deg. and 212 deg. F. It has yet to be raised to 250 deg. F.; and for this purpose the writer saw at once the advantage that would be attained by using a coil of live steam from the boiler. This device does not cause any loss of steam, except the small loss due to radiation, since the water in any case would have to be heated up to the temperature of the steam on entering the boiler. By adopting this method, the chemical precipitation, which would otherwise occur in the boiler, takes place in the heater; and it is only necessary now to provide a filter, which shall prevent anything passing that can possibly cause scale.

Having explained as briefly as possible the principles on which the system is founded, the writer will now describe the details of the heater itself.

In Figs. 1 and 2 are shown an elevation and a vertical section of the heater. The cast-iron base, A, is divided into two parts by the diaphragm, B. The exhaust steam enters at C, passes up the larger tubes, D, which are fastened into the upper shell of the casting, returns by the smaller tubes, E, which are inside the others, and passes away by the passage, F. The inner tube only serves for discharge. It will be seen at once that this arrangement, while securing great heating surface in a small space, at the same time leaves freedom for expansion and contraction, without producing strains. The free area for passage of steam is arranged to be one and a half times that of the exhaust pipe, so that there is no possible danger of back pressure. The wrought iron shell, G, connecting the stand, A, with the dome, H, is made strong enough to withstand the full boiler pressure. An ordinary casing, J, of wood or other material prevents loss by radiation of heat. The cold water from the pump passes into the heater through the injector arrangement, K, and coming in contact with the tubes, D, is heated; it then rises to the coil, L, which is supplied with steam from the boiler, and thus becomes further heated, attaining there a temperature of from 250 deg. to 270 deg. F., according to the pressure in the boiler. This high temperature causes the separation of the dissolved salts; and on the way to the boiler the water passes through the filter, M, becoming thereby freed from all precipitated matter before passing away to the boiler at N. The purpose of the injector, K, and the pipe passing from O to K, is to cause a continual passage of air or steam from the upper part of the dome to the lower part of the heater, so that any precipitate carried up in froth may be again returned to the under side of the filter, in order more effectually to separate it, before any chance occurs of its passing into the boiler.



The filter consists of wood charcoal in the lower half and bone black above firmly held between two perforated plates, as shown. After the heater has been in use for from three to ten hours, according to the nature of the water used, it is necessary to blow out the heater, in order to clear the filter from deposit. To do this, the cock at R is opened, and the water is discharged by the pressure from the boiler. The steam is allowed to pass through the heater for some little time, in order to clear the filter completely. After this operation, all is ready to commence work again. By this means the filter remains fit for use for months without change of the charcoal.

Where a jet condenser is used, either of two plans may be adopted. One plan takes the feed-water from the hot well and passes the exhaust from the feed pumps through the heater, using at the same time an increased amount of coil for the live steam. By this means a temperature of water is attained high enough to cause deposition, and at the same time to produce decomposition of the oil brought over from the cylinders. The other plan places the heater in the line of exhaust from the engine to the condenser, also using a larger amount of coil. Both these methods work well. The writer sometimes uses the steam from the coil to work the feed pump; or, if the heater stands high enough, it is only necessary to make a connection with the boiler, when the water formed by the condensation of the steam runs back to the boiler, and thus the coil is kept constantly at the necessary temperature.

In adapting the heater to locomotives, we were met with the difficulty of want of space to put a heater sufficiently large to handle the extremely large amount of water evaporated on a locomotive worked up to its full capacity, being from 1,500 to 2,500 gallons per hour, or from five hundred to one thousand h.p. We designed various forms of heaters and tried them, but have finally decided on the one shown in the engraving, Fig. 3, which consists of a lap welded tube, 13 inches internal diameter, 12 feet long, with a cast-iron head which is divided into two compartments or chambers by a diaphragm. Into this head are screwed 60 tubes, one inch outside diameter and 12 feet long, which are of seamless brass. These are the heating tubes, within which are internal tubes for circulation only, which are screwed into the diaphragm and extend to within a very short distance of the end of the heating tube. The exhaust steam for heating is taken equally from both sides of the locomotive by tapping a two-inch nipple with a cup shaped extension on it in such a way as to catch a portion of the exhaust without interfering with the free escape of the steam for the blast, and without any back pressure, as it relieves the back pressure as much as it condenses. The pipe from one side of the engine is connected with the chamber into which the heating tubes are screwed, and is in direct communication with them. The pipe from the other side is connected with the chamber into which the circulating tubes are screwed. The beat of the exhaust, working, as it does, on the quarters, causes a constant sawing or backward and forward circulation of steam without any discharge, and only the condensation is carried off.

The water is brought from the pump and discharged into the lower side of the heater well forward, and passes around the heating tubes to the end, when it is discharged into a pipe that carries it forward, either direct to the check or into the purifier, which is located between the frames under the boiler, and consists of a chamber in which are arranged a live steam coil and a filter above the coil. The water coming in contact with the coil, its temperature is increased from the temperature of the exhaust, 210 deg., to about 250 deg. Fahr., which causes the separation of the lime salts as before described, and it then passes through the filter and direct to the boiler from above the filter, which is cleansed by blowing back through it as before described.

One of these heaters lately tested showed a saving in coal of 22 per cent, and an increase of evaporation of 1.09 pounds of water per pound of coal.—Franklin Journal.

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MONTEVERDE'S STATUE OF ARCHITECTURE.

This precious statue forms the noble figure that adorns the monument erected to the memory of the architect Carles Sada, who died in 1873. This remarkable funereal monument is 20 feet high, the superior portion consisting of a sarcophagus resting upon a level base. Upon this sarcophagus is placed the statue of "La Architectura," which we reproduce, and which well exemplifies the genius of the author and sculptor, Juli Monteverde.—La Ilustracio Catalana.



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DESIGN FOR A GARDENER'S COTTAGE.

The illustration shows a gardener's cottage recently erected at Downes, Devonshire, the seat of Colonel Buller, V.C., C.B, C.M.G., from the designs of Mr. Harbottle, A.R.I.B.A., of Exeter. It is built of red brick and tile, the color of which and the outline of the cottage give it a picturesque appearance, seen through the beautiful old trees in one of the finest parks in Devonshire.—The Architect.



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PAPER MAKING "DOWN EAST."

Writing from Gilbertville, a Lewiston journal correspondent says: Gilbertville, a manufacturing community in the town of Canton, twenty-five miles from Lewiston, up the Androscoggin, is now a village of over 500 inhabitants, where three years ago there was but a single farmhouse. If a town had sprung into existence in a far Western State with so much celerity, the phenomenon would not be considered remarkable, perhaps; but growths of this kind are not indigenous to the New England of the present era. Gilbertville has probably outstripped all New England villages in the race of the past three years. It is only one of the signs that old Maine is not dead yet.

Gilbert Brothers erected a saw mill here three years ago. A year later, the Denison Paper Manufacturing Company, of Mechanic Falls, erected a big pulp mill, which, also, the town voted to exempt from taxation for ten years. The mills are valuable companions for each other. The pulp mill utilizes all the waste of the saw mill. A settlement was speedily built by the operatives. Gilbertville now boasts of a post-office, a store, several large boarding houses, a nice school house, and over 500 inhabitants. The pulp mill employs seventy men. It runs night and day. It manufactures monthly 350 cords of poplar and spruce into pulp. It consumes monthly 500 cords of wood for fuel, 45 casks of soda ash, valued at $45 per cask, nine car loads of lime, 24,000 pounds to the car. It produces 1,000,000 pounds of wet fiber, valued at about $17,000, monthly. The pay roll amounts to $3,500 per month.

The larger part of the stock used by the mill consists of poplar logs floated down the Androscoggin and its tributaries. One thousand two hundred cords of poplar cut in four-foot lengths are piled about the mill; and a little further up the river are 5,000 cords more. The logs are hauled from the river and sawed into lengths by a donkey engine, which cuts about sixty cords per day, and pulls out fourteen logs at a time. All the spruce slabs made by the saw mill are used with this poplar. The wood is fed to a wheel armed with many sharp knives. It devours a cord of wood every fifteen minutes. The four-foot sticks are chewed into fine chips as rapidly as they can be thrust into the maw of the chopper. They are carried directly from this machine to the top of the mill by an endless belt with pockets attached. There are hatchways in the attic floor, which open upon rotary iron boilers. Into these boilers the chips are raked, and a solution of lime and soda ash is poured over them.

This bath destroys all the resinous matter in the wood, and after cooking five hours the chips are reduced to a mass of soft black pulp. Each rotary will contain two cords of chips. After the cooking, the pulp is dumped into iron tanks in the basement, where it is thoroughly washed with streams of clean cold water. It is then pumped into a machine which rolls it into broad sheets. These sheets are folded, and condensed by a hydraulic press of 200 tons pressure. This process reduces its bulk fifty per cent., and sends profuse jets of water flying out of it. The soda ash, in which, mixed with lime and water, the chips are cooked, is reclaimed, and used over and over again. The liquor, after it has been used, is pumped into tanks on top of large brick furnaces. As it is heated, it thickens. It is brought nearer and nearer the fire until it crystallizes, and finally burns into an ash. Eighty per cent. of the ash used is thus reclaimed. This process is an immense saving to the pulp manufacturers. The work in the pulp mill is severe, and is slightly tinged with danger.

Three thousand four hundred pounds of white ash to 2,100 pounds of lime are the proportions in which the liquor in each vat is mixed. One does not envy the lot of the stout fellows who crawl into the great rotaries to stow away the chips. The hurry of business is so great that they cannot wait for these boilers to cool naturally, after they have cooked one batch, before putting in another. So they have a fan pump, to which is attached a canvas hose, and with this blow cooling air currents into the boiler, or "rotary," as they call it. The rotary is subjected to an immense pressure, and is very stoutly made of thick iron plates, bolted together.

Describing the business as carried on at Mechanic Falls, the same paper says: There are six of these mills on the three dams over which the Little Androscoggin falls. These are the Eagle, the Star, the Diamond, the Union, the pulp, and the super calendering mills. The Eagle and the Star mills run on book papers of various grades. The Union mill runs on newspaper. The old Diamond mill now prepares pulp stock. The pulp mill does nothing but bleach the rag pulp and prepare for the machines in the other mills; while the super-calendering mill gives the paper an extra finish when ordered. There is practically but one series of processes by which the paper is made in the various mills.

It is a curious fact that America is not ragged enough to produce the requisite amount of stock for its own paper mills. Nearly all the rags used by the Denison Mills (and by others in various parts of the country as well) are imported from the old countries. All the rags first go through the "duster." This is a big cylindrical shell of coarse wire netting. It is rapidly revolved, while a screw running through its center is turned in the opposite direction. Air currents are forced through it by a power fan. The rags are continuously fed into one end of this shell, which is about ten feet long and four feet in diameter. The screw forces them through the whole length of the shell, while they are kept buzzing around and subjected to breezes which blow thick clouds of dirt and dust out of them. The air of the room is thick with European and Asiatic earth. It is swept up in great rolls on the floor. The man who operates the duster should have leather lungs.

Overhead is a long room where thirty girls are busily sorting the rags for the various grades of papers. That the dusting machine is no more perfect than a human machine is evinced by the murky atmosphere of this room, by the particles that lodge in the throat of the visitor, and by the frequent coughing of the sorters. They protect their hair with turbans of veiling, occasionally decorated with a bit of bright color. These turbans give the room the appearance of an industrious Turkish harem. Short, sharp scythe blades, like Turkish scimeters, gleam above all the girls' benches. When a sorter wishes to cut a rag, she pulls it across the edge of this blade, and is not obliged to hunt for a pair of shears.

Curious discoveries are frequently made in the rags. Old pockets, containing small sums of money, are occasionally found. A foreign coin valued at about $3 was found a few days ago. In the paper stock, quaint and valuable old books or pictures are found often. One of the workmen has a museum composed of curiosities found amid the rags and shreds of paper. Rev. Dr. Bolles, of Massachusetts, makes an annual pilgrimage to Mechanic Falls for the sake of the rare old pamphlets, books, and engravings that he may dig out.

Stuffed in hogsheads, the rags are lowered from this room through a hatchway, and are given a red hot lime bath. They are placed in ponderous cylinders of boiler iron, which revolve horizontally in great gears high above the floor. A mixture of lime and water, which has been prepared in large brick vats, is poured over them. An iron door, secured by huge bolts, is closed on them. The cylinder slowly turns around, and churns the rags in the lime-juice twelve hours. This process is called bleaching. When the rags come out they are far from white, however. They are of a uniform dirty brown hue. But the colors have lost their gripe. When the rags shall have been submitted to the grinding and washing in pure water, as we shall see them presently, they are easily whitened. The lime bath is the purgatory of the paper stock.

Before we go any further, we must see what becomes of those soft and lop-sided bundles which are going into the mills. These contain chemically prepared wood fiber, a certain percentage of which is used in nearly all the papers made now. It gives the paper a greater body, although its fiber is not so strong as that made of rags. The pulp comes down from Canton in soft brown sheets. These are at once bleached. The brown fiber is placed in a bath of cold water and chlorate of lime. There it quietly rests till a sediment settles at the bottom of the tank. At an opportune moment the workman pours in a copious libation of boiling water. This causes the escape of the chlorine gas, which destroys all the color in the pulp. In half an hour it comes out, a mass of smoking fibers as white as a snow heap. The drainers into which it goes are large pens with perforated tile floors. The pulp remains in the drainers till it so dry it is handled with a pitchfork.

We are now ready to look at the beating machines, which have to perform a very important part in paper making. These are large iron tanks with powerful grinders revolving in them. Barrow loads of the brown rags are dumped into them, and clear cold water is poured in. The grinders are then started. They chew the rags into fine bits. They keep the mass of rags and water circulating incessantly in the tanks. Clean water constantly flows in and dirty water as constantly flows out. In the course of six hours the rags are reduced to a perfectly white pulpy mass. There is one mill, as we have said, devoted exclusively to the reduction of rags to this white pulp. It is dried in drainers such as we saw a few moments ago filled with the wood fiber.

There are other beating machines just like these, which perform a slightly different service. Their function may be compared to that of an apothecary's mortar or a cook's mixing dish. The white rag stock and the white wood fiber are mixed in these, in the required proportions. At this stage, the pulp is adulterated with China clay, to give it substance and weight; here the sizing (composed of resin and sal soda) is put in; oil of vitriol, bluing, yellow ocher, and other chemicals are added, to whiten or to tint the paper. These beaters are much like so many soup kettles. Upon the kind, number, and proportion of the ingredients depends the nature of the product. The percentages of rag pulp, wood pulp, clay, coloring, etc., used, depend upon the quality of paper ordered.

After the final beating, the mixture descends into a large reservoir called the "stuff chest," whence it is pumped to the paper machine. The pulp is of the consistency of milk when it pours from the spout of the pumps on the paper machine. The latter is a complicated series of rollers, belts, sieves, blankets, pumps, and gears, one hundred feet long. To describe it or to understand a description of it would require the vocabulary and the knowledge of a scientist. The milky pulp first passes over a belt of fine wire cloth, through which the water partly drains. It is ingeniously made to glide over two perforated iron plates, under which pumps are constantly sucking. You can plainly see the broad sheet of pulp lose its water and gain thickness as it goes over these plates. Broad, blanket-like belts of felt take it and carry it over and between large rolling cylinders filled with hot steam. These dry and harden it into a sheet which will support itself; and without the aid of blankets it winds among iron rolls, called calenders, which squeeze it and give it surface. It is wound upon revolving reels at the end of the machine.

If a better surface or gloss is required, it is carried to the super calendering mill, where it is steamed and subjected to a long and circuitous journey up and down tall stands of calenders upon calenders. The paper is cut by machines having long, winding knives which revolve slowly and cut, on the scissors principle—no two points of the blade bearing on the paper with equal pressure at once. Girls pack the sheets on the tables as they fall from the cutters, and throw out the damaged or dirtied sheets. A small black spot or hole or imperfection of any sort is sufficient to reject a sheet. In some orders fifty per cent. of the sheets are thrown out. There is no waste, as the damaged paper is ground into pulp again. Having been cut, the paper must be counted and folded. Then it is packed into bundles for shipment. The young lady who does the counting and folding is the wonder of the mill. Giving the sheets a twist with one hand so as to spread open the edges, she gallops the fingers of the other hand among them; and as quickly as you or I could count three, she counts twenty-four and folds the quire. She takes four sheets with a finger and goes her whole hand and one finger more; thus she gets twenty-four sheets. Long practice is required to do the counting rapidly and accurately. Twenty-four sheets, no more and no less, are always found in her quires.

Papers of different grades are made of different stock, but by the same process. Some paper stock is used. This must be bleached in lime and soda ash. There are powerful steam engines in the mills for use when the water is low. There are large furnaces and boilers which supply the steam used in the processes.

The Messrs. Denison employ 175 hands at Mechanic Falls. Their pay roll amounts to about $5,000 per month. The mills produce 350,000 pounds of paper per month and they ship several car-loads of prepared wood-pulp, in excess of that required for their own use, weekly. The annual value of their product is not far from $300,000. They use, for sundries, each month, 300 tons of coal, 100 casks of common lime, 250 gallons of burning-oil, 28,000 pounds of chlorate of lime, 3,700 pounds of soda ash. 10,000 pounds of resin. 24,000 pounds of sal soda, 22,000 pounds of oil of vitriol, 22,000 pounds of China clay, etc.

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WHEAT-MEAL BREAD AS A MEANS OF DIMINISHING TUBERCULAR DISEASE.

By M. YATES, Hon. Sec. Bread Reform League, London.

It is well recognized that defective mineral nutrition is an important factor in the production of rickets and bad teeth, but as its influence in predisposing toward tuberculous disease is not so clearly ascertained, will you kindly allow public attention to be directed to a statement which was discussed at the Social Science and Sanitary Congresses and which, if confirmed by further scientific research, indicates a simple means of diminishing consumption, which, as Dr. William Fair, F.R.S., says, "is the greatest, the most constant, and the most dreadful of all the diseases that affect mankind." In "Phosphates in Nutrition," by Mr. M.F. Anderson, it is stated that although the external appearances and general condition of a body when death has occurred from starvation are very similar to those presented in tuberculous disease, in starvation, "from wasting of the tissues, caused by the combustion of their organic matter, there would be an apparent increase in the percentage proportion of mineral matter; on the other hand, in tubercular disease, there would be a material decrease in the mineral matter as compared with the general wasting." Analyses, made by Mr. Anderson, of the vascular tissues of patients who have died of consumption, scrofula, and allied diseases, show "a very marked deficiency in the quantity of inorganic matter entering into their composition; this deficiency is not confined to the organs or tissues which are apparently the seat of the disease, but in a greater or lesser degree pervades the whole capillary system."

The observations of Dr. Marcet, F.R.S., show that in phthisis there is a considerable reduction of the normal amount of phosphoric acid in the pulmonary tissues; and it is very probable that there is a general drain of phosphoric acid from the system.

This loss may be caused by the expectoration and night-sweats, or it may also be produced by defective mineral nutrition, either from deficient supply in the food, or from non assimilation. But, whatever causes this deficiency, it is universally acknowledged that it is essential the food should contain a proper supply of the mineral elements. If the body is well nourished, the resisting force of the system is raised. Professor Koch and others, who accept the germ theory of disease to its fullest extent, state that the minute organisms of tubercular disease do not occur in the tissues of healthy bodies, and that when introduced into a living body their propagation and increase are greatly favored by a low state of the general health.