The fibers then must have had an amount of material substance about them to fill the remaining space entirely full, so that a particle of air could not be taken into account anywhere. The cotton has produced the same effect that a solid substance would do if it just filled the space shown above the line, H I, for the water has risen into half the space that is left below it. This enables an overseer to look into the material substance of textile fibers by bringing into use the elasticity of atmospheric air, reserving the liquid process for measuring volume to govern the amount of compressibility.—Boston Journal of Commerce.

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VOLUTE DOUBLE DISTILLING CONDENSER.

This distiller and condenser which we illustrate has been designed, says Engineering, for the purpose of obtaining fresh water from sea water. It is very compact, and the various details in connection with it may be described as follows: Steam from the boiler is admitted into the evaporator through a reducing valve at a pressure of about 60 lb., and passing through the volute, B, evaporates the salt water contained in the chamber, C; the vapor thus generated passing through the pipe, D, into the volute condenser, E, where it is condensed. The fresh water thus obtained flows into the filter, from which it is pumped into suitable drinking tanks.



The steam from the boiler after passing through the volute, B, is conveyed by means of a pipe to the second volute, H, where it is condensed, and the water resulting is conveyed by means of a pump to the hot well or feed tank. The necessary condensing water enters at J and is discharged at K. The method of keeping the supply of salt water in the evaporator at a constant level is very efficient and ingenious. To the main circulating discharge pipe, a small pipe, L, is fitted, which is in communication with the chamber, M, and through this the circulating sea water runs back until it attains a working level in the evaporator, when a valve in the end of pipe, L, is closed by the action of the float, N, the regulation of admission being thus automatic and certain. The steam from the boiler can be regulated by means of a stop valve, and the pressure in the evaporator should not exceed 4 lb., while the pressure gauge is so arranged that the pressure in both condenser and evaporator is shown at the same time. A safety valve is fitted at the top of the condenser, and an automatic blow-off valve, P, is arranged to blow off when a certain density of brine has been attained in the evaporator. The "Esco" triple pump (Fig. 3), which has been specially manufactured for this purpose, has three suctions and deliveries, one for circulating water, the second for the condensed steam, and a third for the filtered drinking water, so that the latter is kept fresh and clean.

The condenser and pumps are manufactured by Ernest Scott & Co., Close Works, Newcastle on Tyne, and were shown by them at the late exhibition in their town.

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IMPROVED CURRENT METER.

Paul Kotlarewsky, of St. Petersburg, has invented an instrument for measuring or ascertaining the velocity of water and air currents.

Upon the shaft or axis of the propeller wheel, or upon a shaft geared therewith, there is a hermetically closed tube or receptacle, D, which is placed at right angles with the shaft, and preferably so that its longitudinal axis shall intersect the axis of said shaft. In this tube or receptacle is placed a weight, such as a ball, which is free to roll or slide back and forth in the tube. The effect of this arrangement is, that as the shaft revolves, the weight will drop alternately toward opposite ends of the tube, and its stroke, as it brings up against either end, will be distinctly heard by the observer as well as felt by him if, as is usually the case, the apparatus when in use is held by him. By counting the strokes which occur during a given period of time, the number of revolutions during that period can readily be ascertained, and from that the velocity of the current to be measured can be computed in the usual way.

When the apparatus is submerged in water, by a rope held by the observer, it will at once adjust itself to the direction of the current. The force of the current, acting against the wings or blades of the propeller wheel, puts the latter in revolution, and the tube, D, will be carried around, and the sliding weight, according to the position of the tube, will drop toward and bring up against alternately opposite ends of said tube, making two strokes for every revolution of the shaft.



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THE FLOWER INDUSTRY OF GRASSE.

A paper on this subject was read before the Chemists' Assistants' Association on March 8, by Mr. F.W. Warrick, and was listened to with much interest.

Mr. Warrick first apologized for presenting a paper on such a frivolous subject to men who had shown themselves such ardent advocates of the higher pharmacy, of the "ologies" in preference to the groceries, perfumeries, and other "eries." But if perfumery could not hope to take an elevated position in the materiae pharmaceuticae, it might be accorded a place as an adjunct, if only on the plea that those also serve who only stand and wait.

Mr. Warrick mentioned that his family had been connected with this industry for many years, and that for many of the facts in the paper he was indebted to a cousin who had had twenty years' practical experience in the South, and who was present that evening.

GRASSE.

The town of Grasse is perhaps more celebrated than any other for its connection with the perfume industry in a province which is itself well known to be its home.

This, the department of the Alpes Maritimes, forms the southeastern corner of France. Its most prominent geographical features are an elevated mountain range, a portion of the Alps, and a long seaboard washed by the Mediterranean—whence the name Alpes Maritimes.

The calcareous hills round Grasse and to the north of Nice are more or less bare, though they were at one time well wooded; the reafforesting of these parts has, however, made of late great progress. Nearer the sea vegetation is less rare, and there many a promontory excites the just admiration of the visitor by its growth of olives, orange and lemon trees, and odoriferous shrubs. Who that has ever sojourned in this province can wonder that Goethe's Mignon should have ardently desired a return to these sunny regions?

Visitors on these shores on the first day of this year found Goethe's lines more poetical than true—

Where a wind ever soft from the blue heaven blows, And the groves are of laurel, and myrtle, and rose;

for they gathered round their fires and coughed and groaned in chorus, and entertained each other with accounts of their ailments. But this was exceptional, and the climate of the Alpes Maritimes is on the whole as near perfection as anything earthly can be. This, however, is not due to its latitude, but rather to its happy protection from the north by its Alps and to its being bathed on the south by the warm Mediterranean and the soft breezes of an eastern wind (which evidently there bears a different reputation to that which it does with us). The mistral, or cold breeze from the hills, is indeed the only climatic enemy, if we except an occasional earthquake.

The town of Grasse itself is situated in the southern portion of the department, and enjoys its fair share of the advantages this situation affords. It is about ten miles from Cannes (Lord Brougham's creation), and, as the crow flies, twenty-five miles from Nice, though about forty miles by rail, for the line runs down to Cannes and thence along the shore to Nice.

Built on the side of a hill some 1,000 feet above the level of the sea, the town commands magnificent views over the surrounding country, especially in the direction of the sea, which is gloriously visible. An abundant stream, the Foux, issuing from the rocks just above the town, is the all productive genius of the place; it feeds a hundred fountains and as many factories, and then gives life to the neighboring fields and gardens.

The population of Grasse is about 12,000, and the flora of its environs represents almost all the botany of Europe. Among the splendid pasture lands, 7,000 feet above the sea, are fields of lavender, thyme, etc. From 7,000 to 6,000 feet there are forests of pine and other gymnosperms. From 6,000 to 4,000 feet firs and the beech are the most prominent trees. Between 4,000 and 2,000 feet we find our familiar friends the oak, the chestnut, cereals, maize, potatoes. Below this is the Mediterranean region. Here orange, lemon, fig, and olive trees, the vine, mulberry, etc., flourish in the open as well as any number of exotics, palms, aloes, cactuses, castor oil plants, etc. It is in this region that nature with lavish hand bestows her flowers, which, unlike their compeers in other lands, are not born to waste their fragrance on the desert air or to die "like the bubble on the fountain," but rather (to paraphrase George Eliot's lofty words) to die, and live again in fats and oils, made nobler by their presence.

The following are the plants put under contribution by the perfume factories of the district, viz., the orange tree, bitter and sweet, the lemon, eucalyptus, myrtle, bay laurel, cherry laurel, elder; the labiates; lavender, spike, thyme, etc.; the umbelliferous fennel and parsley, the composite wormwood and tarragon, and, more delicate than these, the rose, geranium, cassie, jasmin, jonquil, mignonette, and violet.

THE PERFUME FACTORY.

In the perfume factory everything is done by steam. Starting from the engine room at the bottom, the visitor next enters the receiving room, where early in the morning the chattering, patois-speaking natives come to deliver the flowers for the supply of which they have contracted. The next room is occupied with a number of steam-jacketed pans, a mill, and hydraulic presses. Next comes the still room, the stills in which are all heated by steam. In the "extract" department, which is next reached, are large tinned-copper drums, fitted with stirrers, revolving in opposite directions on vertical axes. Descending to the cellar—the coolest part of the building—we find the simple apparatus used in the process of enfleurage. The apparatus is of two kinds. The smaller is a frame fitted with a sheet of stout glass. A number of these, all of the same size, when placed one on the top of the other, form a tolerably air tight box. The larger is a frame fitted with wire netting, over which a piece of molleton is placed. The other rooms are used for bottling, labeling, etc.

The following are some of the details of the cultivation and extraction of perfumes as given in Mr. Warrick's paper:

ORANGE PERFUMES.

The orange tree is produced from the pip, which is sown in a sheltered uncovered bed. When the young plant is about 4 feet high, it is transplanted and allowed a year to gain strength in its new surroundings. It is then grafted with shoots from the Portugal or Bigaradier. It requires much care in the first few years, must be well manured, and during the summer well watered, and if at all exposed must have its stem covered up with straw in winter. It is not expected to yield a crop of flowers before the fourth year after transplantation. The flowering begins toward the end of April and lasts through May to the middle of June. The buds are picked when on the point of opening by women, boys, and girls, who make use of a tripod ladder to reach them. These villagers carry the fruits (or, rather, flowers) of their day's labor to a flower agent or commissionnaire, who weighs them, spreads them out in a cool place (the flowers, not the villagers), where they remain until 1 or 2 A.M.; he then puts them into sacks, and delivers them at the factory before the sun has risen. They are here taken in hand at once; on exceptional days as many as 160 tons being so treated in the whole province. After the following season, say end of June, the farmers prune their trees; these prunings are carted to the factory, where the leaves are separated and made use of.

During the autumn the ground round about the trees is well weeded, dug about, and manured. The old practice of planting violets under the orange trees is being abandoned. Later on in the year those blossoms which escaped extermination have developed into fruits. These, when destined for the production of the oil, are picked while green.

The orange trees produce a second crop of flowers in autumn, sometimes of sufficient importance to allow of their being taken to the factories, and always of sufficient importance to provide brides with the necessary bouquets.

Nature having been thus assisted to deliver these, her wonderful productions, the flowers, the leaves, and the fruits of the orange tree, at the factory, man has to do the rest. He does it in the following manner:

The flowers are spread out on the stone floor of the receiving room in a layer some 6 to 8 inches deep; they are taken in hand by young girls, who separate the sepals, which are discarded. Such of the petals as are destined for the production of orange flower water and neroli are put into a still through a large canvas chute, and are covered with water, which is measured by the filling of reservoirs on the same floor. The manhole of the still is then closed, and the contents are brought to boiling point by the passage of superheated steam through the coils of a surrounding worm. The water and oil pass over, are condensed, and fall into a Florentine receiver, where the oil floating on the surface remains in the flask, while the water escapes through the tube opening below. A piece of wood or cork is placed in the receiver to break up the steam flowing from the still; this gives time for the small globules of oil to cohere, while it breaks the force of the downward current, thus preventing any of the oil being carried away.

The first portions of the water coming from the still are put into large tinned copper vats, capable of holding some 500 gallons, and there stored, to be drawn off as occasion may require into glass carboys or tinned copper bottles. This water is an article of very large consumption in France; our English cooks have no idea to what an extent it is used by the chefs in the land of the "darned mounseer."

The oil is separated by means of a pipette, filtered, and bottled off. It forms the oil of neroli of commerce; 1,000 kilos. of the flowers yield 1 kilo. of oil. That obtained from the flowers of the Bigaradier, or bitter orange, is the finer and more expensive quality.

The delicate scent of orange flowers can be preserved quite unchanged by another and more gentle process, viz., that of maceration. It was noticed by some individual, whose name has not been handed down to us, that bodies of the nature of fat and oil are absorbers of the odor-imparting particles exhaled by plants. This property was seized upon by some other genius equally unknown to fame, who utilized it to transfer the odor of flowers to alcohol.

Where oil is used it is the very finest olive, produced by the trees in the neighborhood. This is put into copper vats holding about 50 gallons; 1 cwt. of flowers is added. After some hours the flowers are strained out by means of a large tin sieve. The oil is treated with another cwt. of flowers and still another, until sufficiently impregnated. It is then filtered through paper until it becomes quite bright; lastly it is put into tins, and is ready for exportation or for use in the production of extracts.

Where fat is employed as the macerating agent, the fat used is a properly adjusted mixture of lard and suet, both of which have been purified and refined during the winter months, and kept stored away in well closed tins.

One cwt. of the fat is melted in a steam-jacketed pan, and poured into a tinned copper vat capable of holding from 5 to 6 cwt. About 1 cwt. of orange flowers being added, these are well stirred in with a wooden spatula. After standing for a few hours, which time is not sufficient for solidification to take place, the contents are poured into shallow pans and heated to 60 deg. C. The mixture thus rendered more fluid is poured on to a tin sieve; the fat passes through, the flowers remain behind. These naturally retain a large amount of macerating liquor. To save this they are packed into strong canvas bags and subjected to pressure between the plates of a powerful hydraulic press. The fat squeezed out is accompanied by the moisture of the flowers, from which it is separated by skimming. Being returned to the original vat, our macerating medium receives another complement of flowers to rob of their scent, and yet others, until the strength of the pomade desired is reached. The fat is then remelted, decanted, and poured into tins or glass jars.

To make the extrait, the pomade is beaten up with alcohol in a special air tight mixing machine holding some 12 gallons, stirrers moved by steam power agitating the pomade in opposite directions. After some hours' agitation a creamy liquid is produced, which, after resting, separates, the alcohol now containing the perfume. By passing the alcohol through tubes surrounded by iced water, the greater part of the dissolved fat is removed.

These are the processes applied to the flowers. The leaves are distilled only for the oil of petit grain. This name was given to the oil because it was formerly obtained from miniature orange fruits. From 1,000 kilos. of leaves 2 kilos. of oil are obtained.

The oil obtained from the fruit of the orange, like that of the lemon, is extracted at Grasse by rolling the orange over the pricks of an ecueille, an instrument with a hollow handle, into which the oil flows. The oil is sometimes taken up by a sponge. Where the oil is produced in larger quantities, as at Messina, more elaborate apparatus is employed. A less fragrant oil is obtained by distilling the raspings of the rind.

THE EUCALYPTUS, MYRTLE, ETC.

Of later introduction than the trees of the orange family is the Eucalyptus globulus, which, not being able to compete with the former in the variety of nasal titillations it gives rise to, probably consoles itself with coming off the distinct victor in the department of power and penetration. The leaves and twigs of this tree are distilled for oil. This oil is in large demand on the Continent, the fact of there being no other species than the globulus in the neighborhood being a guarantee of the uniformity of the product.

Whereas the eucalyptus is but a newcomer in these regions, another member of the same family, the common myrtle, can date its introduction many centuries back. An oil is distilled from its leaves, and also a water.

Associated with the myrtle we find the leaves of the bay laurel, forming the victorious wreaths of the ancients. The oil produced is the oil of bay laurel, oil of sweet bay. This must not be confounded with the oil of bays of the West Indies, the produce of the Myrcia acris; nor yet with the cherry laurel, a member of yet another family, the leaves of which are sometimes substituted for those of the sweet bay. The leaves of this plant yield the cherry laurel water of the B.P. It can hardly be said to be an article of perfumery. It also yields an oil.

Another water known to the British Pharmacopoeia is that produced from the flowers of the elder, which flourishes round about Grasse.

The rue also grows wild in these parts, and is distilled.

THE LABIATES.

The family which overshadows all others in the quantity of essential oils which it puts at the disposal of the Grassois and their neighbors is that of the Labiatae. Foremost among these we have the lavender, spike, thyme, and rosemary. These are all of a vigorous and hardy nature and require no cultivation. The tops of these plants are generally distilled in situ, under contract with the Grasse manufacturer, by the villagers in the immediate vicinity. The higher the altitude at which these grow, the more esteemed the oil. The finest oil of lavender is produced by distilling the flowers only. About 100 tons of lavender, 25 of spike, 40 of thyme, and 20 of rosemary are sent out from Grasse every year.

Among the less abundant labiates of these parts is the melissa, which yields, however, a very fragrant oil.

In the same family we have the sage and the sweet or common basil, also giving up their essential oils on distillation.

THE UMBELLIFERS.

Whereas the flowers of the labiate family are treated by the distillers as favorites are by the gods, and are cut off in their youth, those of the Umbelliferae are allowed to mature and develop into the oil-yielding fruits. Its representatives, the fennel and parsley, grow wild round about the town, and are laid under contribution by the manufacturers.

The Composites are represented by the wormwood and tarragon (Estragon).

THE GERANIUM.

Oil of geranium is produced from the rose or oak-leaved geranium, cuttings of which are planted in well sheltered beds in October. During the winter they are covered over with straw matting. In April they are taken up, and planted in rows in fields or upon easily irrigated terraces. Of water they require quantum sufficit; of nature's other gift, which cheers and not inebriates—the glorious sunshine—they cannot have too much. They soon grow into bushes three or four feet high. At Nice they generally flower at the end of August. At Grasse and cooler places they flower about the end of October. The whole flowering plant is put into the still.

THE ROSE.

Allied to the oil of geranium in odor are the products of the rose. The Rose de Provence is the variety cultivated. It is grown on gentle slopes facing the southeast. Young shoots are taken from a five-year-old tree, and are planted in ground which has been well broken up to a depth of three or four feet, in rows like vines. When the young plant begins to branch out, the top of it is cut off about a foot from the ground. During the first year the farmer picks off the buds that appear, in order that the whole attention of the plant may be taken up in developing its system. In the fourth or fifth year the tree is in its full yielding condition. The flowering begins about mid-April, and lasts through May to early June. On some days as many as 150 tons of roses are gathered in the province of the Alpes Maritimes.

The buds on the point of opening are picked in the early morning. Scott says they are "sweetest washed with morning dew." The purchaser may think otherwise where the dew has to be paid for.

The flowering season over, the trees are allowed to run wild. In January they are pruned, and the branches left are entwined from tree to tree all along the line, and form impenetrable fences.

A rose tree will live to a good age, but does not yield much after its seventh year. At that period it is dug up and burned, and corn, potatoes, or some other crop is grown on the land for twelve months or more.

In the factory the petals are separated from the calyx, and are distilled with water for the production of rose water and the otto. For the production of the huile and pomade they are treated by maceration. They are finished off, however, by the process of enfleurage, in which the frames before alluded to are made use of. The fat, or pomade, is spread on to the glass on both sides. The blossoms are then lightly strewn on to the upper surface. A number of trays so filled are placed one on the top of the other to a convenient height, forming a tolerably air tight box. The next day the old flowers are removed, and fresh ones are substituted for them. This is repeated until the fat is sufficiently impregnated. From time to time the surface of the absorbent is renewed by serrating it with a comb-like instrument. This, of course, is necessary in order to give the hungry, non-saturated lower layers a chance of doing their duty.

Where oil is the absorbent, the wired frames are used in connection with cloths. The cloth acts as the holder of the oil, and the flowers are spread upon it, and the process is conducted in the same way as with the frames with glass.

From the pomade the extrait de rose is made in the same way as the orange extrait.

CASSIE.

The stronger, though less delicate, cassie is grown from seeds, which are contained in pods which betray the connection of this plant with the leguminous family. After being steeped in water they are sown in a warm and well sheltered spot. When two feet high the young plant is grafted and transplanted to the open ground—ground well exposed to the sun and sheltered from the cold winds. It flourishes best in the neighborhood of Grasse and Cannes. The season of flowering is from October to January or February, according to the presence or absence of frost. The flowers are gathered twice a week in the daytime, and are brought to the factories in the evening. They are here subjected to maceration.

JONQUIL.

A plant of humbler growth is the jonquil. The bulbs of this are set out in rows. The flowers put in an appearance about the end of March, four or five on each stem. Each flower as it blooms is picked off at the calyx. They are treated by maceration and enfleurage, chiefly the latter. The harvesting period of the jonquil is of very short duration, and it often takes two seasons for the perfumer to finish off his pomades of extra strength. The crop is also very uncertain.

JASMIN.

A more reliable crop is that of the jasmin. This plant is reared from cuttings of the wild jasmin, which are put in the earth in rows with trenches between. Level ground is chosen; if hillside only is available, this is formed into a series of terraces. When strong enough, the young stem is grafted with shoots of the Jasminum grandiflorum. The first year it is allowed to run wild, the second it is trained by means of rods, canes and other appliances. At the approach of winter the plants are banked up with earth to half their height. The exposed parts then die off. When the last frost of winter is gone the earth is removed, and what remains of the shrub is trimmed and tidied up for the coming season. It grows to four or five feet. Support is given by means of horizontal and upright poles, which join the plants of one row into a hedge-like structure. Water is provided by means of the ditches already mentioned. When not used for this purpose, the trenches allow of the passage of women and children to gather the flowers. These begin to appear in sufficient quantity to repay collecting about the middle of July. The jasmin is collected as soon as possible after it blooms. This occurs in the evening, and up to about August 15, early enough for the blossoms to be gathered the same day. They are delivered at the factories at once, where they are put on to the chassis immediately; the work on them continuing very often till long after midnight. Later on in the year they are gathered in the early morning directly the dew is off. The farmer is up betimes, and as soon as he sees the blossoms are dry he sounds a bugle (made from a sea shell) to announce the fact to those engaged to pick for him.

TUBEROSE.

The tuberose is planted in rows in a similar way to the jasmin. The stems thrown up by the bulbs bear ten or twelve flowers. Each flower as it blooms is picked off. The harvesting for the factories takes place from about the first week in July to the middle of October. There is an abundant yield, indeed, after this, but it is only of service to the florist, the valued scent not being present in sufficient quantity. The flowers are worked up at the factory directly they arrive by the enfleurage process.

MIGNONETTE.

The reseda, or mignonette, is planted from seed, as here in England. The flowering tops are used to produce the huile or pomade.

VIOLETS.

Last in order and least in size comes the violet. For "the flower of sweetest smell is shy and lowly," and has taken a modest place in the paper.

Violets are planted out in October or April. October is preferred, as it is the rainy season; nor are the young plants then exposed to the heat of the sun or to the drought, as they would be if starting life in April.

The best place for them is in olive or orange groves, where they are protected from the too powerful rays of the sun in summer and from the extreme cold in winter. Specks of violets appear during November. By December the green is quite overshadowed, and the whole plantation appears of one glorious hue. For the leaves, having developed sufficiently for the maintenance of the plant, rest on their oars, and seem to take a silent pleasure in seeing the young buds they have protected shoot past them and blossom in the open.

The flowers are picked twice a week; they lose both color and flavor if they are allowed to remain too long upon the plant. They are gathered in the morning, and delivered at the factories by the commissionnaires or agents in the afternoon, when they are taken in hand at once.

The products yielded by this flower are prized before all others in the realms of perfumery, and cannot be improved; for, as one great authority on all matters has said: "To throw a perfume on the violet ... were wasteful and ridiculous excess."

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HOW TO MAKE PHOTO. PRINTING PLATES.

The drawing intended for reproduction is pinned on a board and placed squarely before a copying camera in a good, even light. The lens used for this purpose must be capable of giving a perfectly sharp picture right up to the edges, and must be of the class called rectilinear, i.e., giving straight lines. The picture is then accurately focused and brought to the required size. A plate is prepared in the dark room by the collodion process, which is then exposed in the camera for the proper time and developed in the ordinary way. After development, the plate is fixed and strongly intensified, in order to render the white portions of the drawings as opaque as possible. On looking through a properly treated negative of this kind, it will be seen that the parts representing the lines and black portions of the drawing are clear glass, and the whites representing the paper a dense black.

The negative, after drying, is ready for the next operation, i.e., printing upon zinc. This is done in several ways. One method will, however, be sufficient for the purpose here. I obtain a piece of the bichromatized gelatine paper previously mentioned, and place it on the face of the negative in a printing frame. This is exposed to sunlight (if there is any) or daylight for a period varying from five to thirty minutes, according to the strength of the light. This exposed piece of paper is then covered all over with a thin coating of printing ink, and wetted in a bath of cold water. In a few minutes the ink leaves the white or protected parts of the paper, remaining only on the lines where the light has passed through the negative and affected the gelatine. We now have a transcript of the drawing in printing ink, on a paper which, as soon as dry, is ready for laying down on a piece of perfectly clean zinc, and passing through a press. The effect and purpose of passing this cleaned sheet of zinc through the press in contact with the picture on the gelatine paper is this: Owing to the stronger attraction of the greasy ink for the clean metal than for the gelatine, it leaves its original support, and attaches itself strongly to the zinc, giving a beautifully sharp and clean impression of our original drawing in greasy ink on the surface of the zinc. The zinc plate is next damped and carefully rolled up with a roller charged with more printing ink, and the image is thus made strong enough to resist the first etching. This etching is done in a shallow bath, which is so arranged that it can be rocked to and fro. For the first etching, very weak solution of nitric acid and water is used. The plate is placed with this acid solution in the bath, and steadily rocked for five or ten minutes. The plate is then taken out, washed, and again inked; then it is dusted over with powdered resin, which sticks to the ink on the plate. After this the plate is heated until the ink and resin on the lines melt together and form a strong acid-resisting varnish over all the work. The plate is again put into the acid etching bath and further etched. These operations are repeated five or six times, until the zinc of the unprotected or white part of the picture is etched deep enough to allow the lines to be printed clean in a press, like ordinary type or an engraved wood block. I ought perhaps to explain that between each etching the plate is thoroughly inked, and that this ink is melted down the sides of the line, so as to protect the sides as well as the top from the action of the acid; were this neglected, the acid would soon eat out the lines from below. The greatest skill and care is, therefore, necessary in this work, especially so in the case of some of the exquisitely fine blocks which are etched for some art publications.

There are many details which are necessary to successful etching, but those now given will be sufficient to convey to you generally the method of making the zinc plate for the typographic block. After etching there only remains the trimming of the zinc, a little touching up, and mounting it on a block of mahogany or cherry of exact thickness to render it type high, and it is now ready for insertion with type in the printer's form. From a properly etched plate hundreds of thousands of prints may be obtained, or it may be electrotyped or stereotyped and multiplied indefinitely.—G.S. Waterlow, Brit. Jour. Photo.

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ANALYSIS OF A HAND FIRE GRENADE.

By CHAS. CATLETT and R.C. PRICE.

The analyses of several of these "fire extinguishers" have been published, showing that they are composed essentially of an aqueous solution of one or more of the following bodies; sodium, potassium, ammonium, and calcium chlorides and sulphates, and in small amount borax and sodium acetate; while their power of extinguishing fire is but three or fourfold that of water.

One of these grenades of a popular brand of which I have not found an analysis was examined by Mr. Catlett with the following results: The blue corked flask was so open as to show that it contained no gas under pressure, and upon warming its contents, but 4 or 5 cubic inches of a gas were given off. The grenade contained about 600 c.c. of a neutral solution, which gave on analysis:

In 1000 c.c. In the Flask. Grammes. Grains. Calcium chloride 92.50 850.8 Magnesium " 18.71 173.2 Sodium " 22.20 206.9 Potassium " 1.14 10.6 ——— ——— 134.55 1241.5 Trace of bromide.

As this mixture of substances naturally suggested the composition of the "mother liquors" from salt brines, Mr. Price made an analysis of such a sample of "bittern" from the Snow Hill furnace, Kanawha Co., W.Va., obtaining the following composition:

In 1000 c.c. In 200 c.c. Grammes. Grains. Calcium chloride 299.70 925.8 Magnesium " 56.93 175.7 Strontium " 1.47 4.5 Sodium " 20.16 62.2 Potassium " 5.13 15.8 ——— ——— 383.39 1184.0 Trace of bromide.

There is of course some variation in the bittern obtained from different brines, but it appears of interest to call attention to this correspondence in composition, as indicating that the liquid for filling such grenades is obtained by adding two volumes of water to one of the "bittern." The latter statement is fairly proved by the presence of the bromine, and certainly from an economical standpoint such should be its method of manufacture.—Amer. Chem. Jour.

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MOLECULAR WEIGHTS.

A new and most valuable method of determining the molecular weights of non-volatile as well as volatile substances has just been brought into prominence by Prof. Victor Meyer (Berichte, 1888, No. 3). The method itself was discovered by M. Raoult, and finally perfected by him in 1886, but up to the present has been but little utilized by chemists. It will be remembered that Prof. Meyer has recently discovered two isomeric series of derivatives of benzil, differing only in the position of the various groups in space. If each couple of isomers possess the same molecular weight, a certain modification of the new Van't Hoff-Wislicenus theory as to the position of atoms in space is rendered necessary; but if the two are polymers, one having a molecular weight n times that of the other, then the theory in its present form will still hold. Hence it was imperative to determine without doubt the molecular weight of some two typical isomers. But the compounds in question are not volatile, so that vapor density determinations were out of the question. In this difficulty Prof. Meyer has tested the discovery of M. Raoult upon a number of compounds of known molecular weights, and found it perfectly reliable and easy of application. The method depends upon the lowering of the solidifying point of a solvent, such as water, benzine, or glacial acetic acid, by the introduction of a given weight of the substance whose molecular weight is to be determined. The amount by which the solidifying point is lowered is connected with the molecular weight, M, by the following extremely simple formula: M = T x (P / C); where C represents the amount by which the point of congelation is lowered, P the weight of anhydrous substance dissolved in 100 grammes of the solvent, and T a constant for the same solvent readily determined from volatile substances whose molecular weights are well known. On applying this law to the case of two isomeric benzil derivatives, the molecular weights were found, as expected, to be identical, and not multiples; hence Prof. Meyer is perfectly justified in introducing the necessary modification in the "position in space" theory. Now that this generalization of Raoult is placed upon a secure basis, it takes its well merited rank along with that of Dulong and Petit as a most valuable means of checking molecular weights, especially in determining which of two or more possible values expresses the truth.—Nature.

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[Continued from SUPPLEMENT, No. 642, page 10258.]



THE DIRECT OPTICAL PROJECTION OF ELECTRO-DYNAMIC LINES OF FORCE AND OTHER ELECTRO-DYNAMIC PHENOMENA.[1]

[Footnote 1: An expansion of two papers read before the A.A.A.S. at the Ann Arbor meeting.]

By Prof. J.W. MOORE.

II. LOOPS.

If the wire, with its lines of force, be bent into the form of a vertical circle 1-1/8 in. in diameter, and fixed in a glass plate, some of the lines of force will be seen parallel to the axis of the circle. If the loop is horizontal, the lines become points.



FIELDS OF LOOPS AND MAGNETS.

Place now a vertical loop opposite to the pole of a short bar magnet cemented to the glass plate with the N pole facing it. If the current passes in one direction the field will be as represented by Fig. 14b; if it is reversed by the commutator, Fig. 14c is an image of the spectrum. Applying Faraday's second principle, it appears that attraction results in the first case, and repulsion in the second. The usual method of stating the fact is, that if you face the loop and the current circulates from left over to right, the N end of the needle will be drawn into the loop.



It thus becomes evident that the loop is equivalent to a flat steel plate, one surface of which is N and the other S. Facing the loop if the current is right handed, the S side is toward you.

TO SHOW THE ACTUAL ATTRACTION AND REPULSION OF A MAGNET BY A "MAGNETIC SHELL."

Produce the field as before (Fig. 14), carry a suspended magnetic needle over the field. It will tend to place itself parallel to the lines of force, with the N pole in such a position that, if the current passes clockwise as you look upon the plane of the loop, it will be drawn into the loop. Reversing the position of the needle or of current will show repulsion.

Clerk Maxwell's method of stating the fact is that "every portion of the circuit is acted on by a force urging it across the lines of magnetic induction, so as to include a greater number of these lines within the embrace of the circuit."[2]

[Footnote 2: Electricity and Magnetism, Maxwell, p. 137, Sec.Sec. 489, 490.]

If the horizontal loop is used (Fig. 14a), the needle tries to assume a vertical position, with the N or S end down, according to the direction of the current.

If it is desired to show that if the magnet is fixed and the loop free, the loop will be attracted or repelled, a special support is needed.



A strip (Fig. 15) of brass, J, having two iron mercury cups, K{1} K{2}, screwed near the ends, one insulated from the strip, is fastened upon the horizontal arm of the ring support, Fig. 9, already described. The cups may be given a slight vertical motion for accurate adjustment. Small conductors (Figs. 16, 17, 18), which are circles, rectangles, solenoids, etc., may be suspended from the top of the plate by unspun silk, with the ends dipping into the mercury. The apparatus is therefore an Ampere's stand, with the weight of the movable circuit supported by silk and with means of adjusting the contacts. The rectangles or circles are about two inches in their extreme dimension. Horizontal and vertical astatic system are also used—Figs. 18, 18a. The apparatus may be used with either the horizontal or vertical lantern.



If the rectangle or circle is suspended and a magnet brought near it when the current passes, the loop will be attracted or repelled, as the law requires. The experiments usually performed with De la Rive's floating battery may be exhibited.

The great similarity between the loop and the magnet may be shown by comparing the fields above (Figs. 14b, 14c) with the actual fields of two bar magnets, Figs. 19, 19a.

It will be noticed that the lines in Fig. 19, where unlike poles are opposite, are gathered together as in Fig. 14b,—where the N end of the magnet faces the S side of the magnetic shell; and that in 19a, where two norths face, the line of repulsion has the same general character as in 14c, in which the N end of the magnet faces the N side of the shell.



Instead of placing the magnet perpendicular to the plane of the loop, it may be placed parallel to its plane. Fig. 14d shows the magnet and loop both vertical.

The field shows that the magnet will be rotated, and will finally take for stable equilibrium an axial position, with the N end pointing as determined by the rule already given.



If two loops are placed with their axes in the same straight line as follows, Figs. 14f, 14g, a reproduction of Figs. 14b and 14c will become evident.

It is obvious from these spectra that the two loops attract or repel each other according to the direction of the current, which fact may be shown by bringing a loop near to another loop suspended from the ring stand, Fig. 9, or by using the ordinary apparatus for that purpose—De la Rive's battery and Ampere's stand.



If two loops are placed in the same vertical plane, as in Figs. 14h and 14i, there will be attraction or repulsion, according to the direction of the adjacent currents. The fields become the same as Figs. 8 and 8a, as may be seen by comparing them with those figures.



Having thus demonstrated the practical identity of a loop and a magnet, we proceed to examine the effects produced by loops on straight wires.

If the loop is placed with a straight wire in its plane along one edge, there will be attraction or repulsion, according to the direction of the two currents, Figs. 20 and 20a, which are obviously the same as Figs. 8 and 8a.



If the wire is placed parallel to the plane of the loop and to one side, Figs. 20b and 20c, there will be rotation (same as Figs. 4b and 4c).

If the loop is horizontal and the wire vertical and on one side, the Figs. 20d, 20e are the same as 4d and 4e.

If the loop is horizontal and the wire vertical and axial, 20f and 20g, there will be rotation, and the figures are mere duplicates of 4g and 4h.



Fig. 20h shows a view of 20f when the wire is horizontal and the plane of the loop vertical. It is like 4i.

To verify these facts, suspend a loop from Ampere's stand, Fig. 9, and bring a straight wire near.

A small rectangle or circle may be hung in a similar manner. When the circuit is closed, it tends to place itself with its axis in a N and S direction through the earth's influence. The supposition of an E and W horizontal earth current will explain this action.

To exemplify rotation of a vertical wire by a horizontal loop, Fig. 21 may be shown.

A circular copper vessel with a glass bottom (Fig. 21) has wound around its rim several turns of insulated wire. In the center of the vessel is a metallic upright upon the top of which is balanced in a mercury cup a light copper [inverted U] shaped strip. The ends of the inverted U dip into the dilute sulphuric acid contained in the circular vessel.

The current passes from, the battery, up the pillar, down the legs of the U to the liquid, thence through the insulated wire back to the battery.



This is the usual form of apparatus, modified in size for the vertical or horizontal lantern.

(To be continued.)

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POISONS.

"Poisons and poisoning" was the subject of a discourse a few days ago at the Royal Institution. The lecturer, Professor Meymott Tidy, began by directing attention to the derivation of the word "toxicology," the science of poisons. The Greek word [Greek: toxon] signified primarily that specially oriental weapon which we call a bow, but the word in the earliest authors included in its meaning the arrow shot from the bow. Dioscorides in the first century A.D. uses the word [Greek: to toxikon] to signify the poison to smear arrows with. Thus, by giving an enlarged sense to the word—for words ever strive to keep pace, if possible, with scientific progress, we get our modern and significant expression toxicology as the science of poisons and of poisoning. A certain grim historical interest gathers around the story of poisons.

It is a history worth studying, for poisons have played their part in history. The "subtil serpent" taught men the power of a poisoned fang. Poison was in the first instance a simple instrument of open warfare. Thus, our savage ancestors tipped their arrows with the snake poison in order to render them more deadly. The use of vegetable extracts for this purpose belongs to a later period. The suggestion is not unreasonable that if war chemists with their powders, their gun cotton, and their explosives had not been invented, warlike nations would have turned for their instrumenta belli to toxicologists and their poisons. At any rate, the toxicologists may claim that the very cradle of science was rocked in the laboratory of the toxicological worker. Early in the history of arrow tipping the admixture of blood with the snake poison became a common practice. Even the use of animal fluids alone is recorded—e.g., the arrows of Hercules, which were dipped in the gall of the Lernaean hydra. Hercules himself at last fell a victim to the blood stained tunic of the dead Centaur Nessus. As late as the middle of the last century Blumenbach persuaded one of his class to drink 7 oz. of warm bullock's blood in order to disprove the then popular notion that even fresh blood was a poison. The young man who consented to drink the blood did not die a martyr to science.

The first important question we have to answer is, What do we mean by a poison? The law has not defined a poison, although it requires at times a definition. The popular definition of a poison is "a drug which destroys life rapidly when taken in small quantity." The terms "small quantity" as regards amount, and "rapidly" as regards time, are as indefinite as Hodge's "piece of chalk" as regards size. The professor defined a poison as "any substance which otherwise than by the agency of heat or electricity is capable of destroying life, either by chemical action on the tissues of the living body or by physiological action by absorption into the living system." This definition excepted from the list of poisons all agencies that destroyed life by a simple mechanical action, thus drawing a distinction between a "poison" and a "destructive thing." It explains why nitrogen is not a poison and why carbonic acid is, although neither can support life. This point the lecturer illustrated. A poison must be capable of destroying life. It was nonsense to talk of a "deadly poison." If a body be a poison, it is deadly; if it be not deadly, it is not a poison. Three illustrations of the chemical actions of poisons were selected. The first was sulphuric acid. Here the molecular death of the part to which the acid was applied was due to the tendency of sulphuric acid to combine with water. The stomach became charred. The molecular death of certain tissues destroyed the general functional rhythmicity of the system until the disturbance became general, somatic death (that is, the death of the entire body) resulting. The second illustration was poisoning by carbonic oxide. The professor gave an illustrated description of the origin and properties of the coloring matter of the blood, known as haemoglobin, drawing attention to its remarkable formation by a higher synthetical act from the albumenoids in the animal body, and to the circumstance that, contrary to general rule, both its oxidation and reduction may be easily effected. It was explained that on this rhythmic action of oxidizing and reducing haemoglobin life depended.

Carbonic oxide, like oxygen, combined with haemoglobin, produced a comparatively stable compound; at any rate, a compound so stable that it ceased to be the efficient oxygen carrier of normal haemoglobin. This interference with the ordinary action of haemoglobin constituted poisoning by carbonic oxide. In connection with this subject the lecturer referred to the use of the spectroscope as an analytical agent, and showed the audience the spectrum of blood extracted from the hat of the late Mr. Briggs (for the murder of whom Muller was executed), and this was the first case in which the spectroscopic appearances of blood formed the subject matter of evidence. The third illustration of poisoning was poisoning by strychnine. Here again the power of the drug for undergoing oxidation was illustrated. It was noted that although our knowledge of the precise modus operandi of the poison was imperfect, nevertheless that the coincidence of the first fit in the animal after its exhibition with the formation of reduced haemoglobin in the body was important.

There followed upon this view of the chemical action of poison in the living body this question: Given a knowledge of certain properties of the elements—for example, their atomic weights, their relative position according to the periodic law, their spectroscopic character, and so forth—or given a knowledge of the molecular constitution, together with the general physical and chemical properties of compounds—in other words, given such knowledge of the element or compound as may be learned in a laboratory—does such knowledge afford us any clew whereby to predicate the probable action of the element or of the compound respectively on the living body? The researches of Blake, Rabuteau, Richet, Bouchardat, Fraser, and Crum-Brown were discussed, the results of their observations being that at present we were unable to determine toxicity or physiological action by any general chemical or physical researches. The lecturer pointed out that such relationship was scarcely to be expected. Poisons acted on different tissues, while even the same poison, according to the dose administered and other conditions, expended its toxic activity in different ways.

Further, the allotropic modifications of elements and the isomerism of compounds increased the difficulties. Why should yellow phosphorus be an active poison and red phosphorus be inert? Why should piperine be the poison of all poisons to keep you awake, and morphine the poison of all poisons to send you asleep, although to the chemist these two bodies were of identical composition? The lecturer urged that the science of medicine (for the poisons of the toxicologist were the medicines of the physician) must be experimental. Guard jealously against all wanton cruelty to animals; but to deprive the higher creation of life and health lest one of the lower creatures should suffer was the very refinement of cruelty. "Are ye not of much more value then they?" spoke a still small voice amid the noisy babble of well intentioned enthusiasts.—London Times.

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ARTIFICIAL MOTHER FOR INFANTS.

All the journals have recently narrated the curious story of the triplets that were born prematurely at the clinic of Assas Street. Placed at their birth in an apparatus constructed on the principle of an incubator, in order to finish their development therein, these frail beings are doing wonderfully well, thanks to the assiduous care bestowed upon them, and are even showing, it appears, a true emulation to become persons of importance.

Every one now knows the incubator or "artificial hen"—that box with a glass top in which, under the influence of a mild heat, hens' eggs, laid upon wire cloth, hatch of themselves in a few days, and allow pretty little chicks to make their way out of the cracked shell.

This ingenious apparatus, which has been adopted by most breeders, gives so good results that it has already supplanted the mother hens in all large poultry yards, and at present, thanks to it, large numbers of eggs that formerly ended in omelets are now changing into chickens.

Although not belonging to the same race, a number of children at their birth are none the less delicate than these little chicks.

There are some that are so puny and frail among the many brought into the world by the anaemic and jaded women of the present generation that, in the first days of their existence, their blood, incapable of warming them, threatens at every instant to congeal in their veins. There are some which, born prematurely, are so incapable of taking nourishment of themselves, of breathing and of moving, that they would be fatally condemned to death were not haste made to take up their development where nature left it, in order to carry it on and finish it. In such a case it is not, as might be supposed, to the exceptionally devoted care of the mother that the safety of these delicate existences is confided. As the sitting hen often interferes with the hatching of her eggs by too much solicitude, so the most loving and attentive mother, in this case, would certainly prove more prejudicial than useful to her nursling. So, for this difficult task that she cannot perform, there is advantageously substituted for her what is known as an artificial mother. This apparatus, which is identical with the one employed for the incubation of chickens, consists of a large square box, supporting, upon a double bottom, a series of bowls of warm water. Above these vessels, which are renewed as soon as the temperature lowers, is arranged a basket filled with cotton, and in this is laid, as in a nest, the weak creature which could not exist in the open air.



Through the glass in the cover, the mother has every opportunity of watching the growth of her new born babe; but this is all that she is allowed to do. The feeding of the infant, which is regulated by the physician at regular hours, is effected by means of a special rubber apparatus, through the aid of an intelligent woman who has sole charge of this essential operation. The aeration of the little being, which is no less important, is assured by a free circulation, in the box, of pure warm air, which is kept at a definite temperature and is constantly renewed through a draught flue. The least variations in the temperature are easily seen through a horizontal thermometer placed beneath the glass.

Thus protected against all those bad influences that are often so fatal at the inception of life, even to the healthiest babes, preserved from an excess or insufficiency of food, sheltered from cold and dampness, protected against clumsy handling and against pernicious microbes, sickly or prematurely born babies soon acquire enough strength in the apparatus to be able, finally, like others, to face the various perils that await us from the cradle.

The results that have been obtained for some time back at Paris, where the surroundings are so unfavorable, no longer leave any doubt as to the excellence of the process. At the lying-in clinic of Assas Street, Doctors Farnier, Chantreuil, and Budin succeeded in a few days in bringing some infants born at six months (genuine human dolls, weighing scarcely more than from 21/4 to 41/2 pounds) up to the normal weight of 71/2 pounds.—L'Illustration.

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GASTROSTOMY.

Surgery has, as is well known, made great progress in recent years. Apropos of this subject, we shall describe to our readers an operation that was recently performed by one of our most skillful surgeons, Dr. Terrillon, under peculiar circumstances, in which success is quite rare. The subject was a man whose oesophagus was obstructed, and who could no longer swallow any food, or drink the least quantity of liquid, and to whom death was imminent. Dr. Terrillon made an incision in the patient's stomach, and, through a tube, enabled him to take nourishment and regain his strength. We borrow a few details concerning the operation from a note presented by the doctor at one of the last meetings of the Academy of Medicine.



Mr. X., fifty-three years of age, is a strong man of arthritic temperament. He has suffered for several years with violent gastralgia and obstinate dyspepsia, for which he has long used morphine. The oesophagal symptoms appear to date back to the month of September, 1887, when he had a painful regurgitation of a certain quantity of meat that he had swallowed somewhat rapidly.

Since that epoch, the passage of solid food has been either painful or difficult, and often followed by regurgitation. The food seemed to stop at the level of the pit of the stomach. So he gave up solid food, and confined himself to liquids or semi-liquids, which readily passed up to December 20, 1887. At this epoch, he remarked that liquids were swallowed with difficulty, especially at certain moments, they remaining behind the sternum and afterward slowly descending or being regurgitated. This state of things was more marked especially in the first part of January. He was successfully sounded several times, but soon the sound was not able to pass. Doctors Affre and Bazenet got him to come to Paris, where he arrived February 5, 1888.

For ten days, the patient had not been able to swallow anything but about a quart of milk or bouillon in small doses. As soon as he had swallowed the liquid, he experienced distress over the pit of the stomach, followed by painful regurgitations. For three days, every attempt made by Dr. Terrillon to remove the obstacle that evidently existed at the level of the cardia entirely failed. Several times after such attempts a little blood was brought out, but there was never any hemorrhage.

The patient suffered, grew lean and impatient, and was unable to introduce into his stomach anything but a few spoonfuls of water from time to time. As he was not cachectic and no apparent ganglion was found, and as his thoracic respiration was perfect, it seemed to be indicated that an incision should be made in his stomach. The patient at once consented.

The operation was performed February 9, at 11 o'clock, with the aid of Dr. Routier, the patient being under the influence of chloroform. A small aperture was made in the wall of the stomach and a red rubber sound was at once introduced in the direction of the cardia and great tuberosity. This gave exit to some yellowish gastric liquid. The tube was fixed in the abdominal wall with a silver wire. The operation took three quarters of an hour. The patient was not unduly weakened, and awoke a short time afterward. He had no nausea, but merely a burning thirst. The operation was followed by no peritoneal reaction or fever. Three hours afterward, bouillon and milk were injected and easily digested.

Passing in silence the technical details, which would not interest the majority of our readers, we shall be content to say that Mr. X., thanks to this alimentation, has regained his strength, and is daily taking his food as shown in Fig. 1. The aperture made in the stomach permits of the introduction of the rubber apparatus shown in Fig. 2, the object of which is to prevent the egress of the liquids of the stomach and at the same time to introduce food. A funnel is fitted to the tube, and the liquid or semi-liquid food is directly poured into the stomach. Digestion proceeds with perfect regularity, and Mr. X., who has presented himself, of his own accord, before the Academy, and whom we have recently seen, has resumed his health and good spirits.—La Nature.

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HOW TO CATCH AND PRESERVE MOTHS AND BUTTERFLIES.

There is no part of our country in which one cannot form a beautiful local collection, and any young person who wants amusement, instruction, and benefit from two, three, or more weeks in the country can find all in catching butterflies and moths, arranging them, and studying them up.

Provide yourself first with two tools, a net and a poison bottle. The net may be made of any light material. I find the thinnest Swiss muslin best. Get a piece of iron wire, not as heavy as telegraph wire, bend it in a circle of about ten inches diameter, with the ends projecting from the circle two or three inches; lash this net frame to the end of a light stick four or five feet long. Sew the net on the wire. The net must be a bag whose depth is not quite the length of your arm—so deep that when you hold the wire in one hand you can easily reach the bottom with the bottle (to be described) in the other hand. Never touch wing of moth or butterfly with your fingers. The colors are in the dusty down (as you call it), which comes off at a touch. Get a glass bottle or vial, with large, open mouth, and cork which you can easily put in and take out. The bottles in which druggists usually get quinine are the most convenient. It should not be so large that you cannot easily carry it in your pocket. Let the druggist put in the bottle a half ounce of cyanide of potassium; on this pour water to the depth of about three-fourths of an inch, and then sprinkle in and mix gently and evenly enough plaster of Paris to form a thick cream, which will set in a cake in the bottom of the vial. Let it stand open an hour to set and dry, then wipe out the inside of the vial above the cake and keep it corked. This is the regular entomological poison bottle, used everywhere. An insect put in it dies quietly at once. It will last several months.

These two tools, the net and the poison bottle, are your catching and killing instruments. You know where to look for butterflies. Moths are vastly more numerous, and while equally beautiful, present more varieties of beauty than butterflies. They can be found by daylight in all kinds of weather, in the grass fields, in brush, in dark woods, sometimes on flowers. Many spend the daytime spread out, others with close shut wings on the trunks of trees in dark woods. The night moths are more numerous and of great variety. They come around lamps, set out on verandas in the night, in great numbers. A European fashion is to spread on tree trunks a sirup made of brown sugar and rum, and visit them once in a while at night with net and lantern. Catch your moth in the net, take him out of it by cornering him with the open mouth of your poison bottle, so that you secure him unrubbed.

Now comes the work of stretching your moths. This is easy, but must be done carefully. Provide your own stretching boards. These can be made anywhere with hammer and nail and strips of wood. You want two flat strips of wood about seven-eighths or three-fourths of an inch thick and eight to fourteen inches long, nailed parallel to each other on another strip, so as to leave a narrow open space between the two parallel strips. Make two or three or more of these, with the slit or space between the strips of various widths, for large and small moths and butterflies. Make as many of them, with as various widths of slit, as your catches may demand. Take your moth by the feet, gently in your fingers, put a long pin down through his body, set the pin down in the slit of the stretching board, so that the body of the moth will be at the top of the slit and the wings can be laid out flat on the boards on each side. Have ready narrow slips of white paper. Lay out one upper wing flat, raising it gently and carefully by using the point of a pin to draw it with, until the lower edge of this upper wing is nearly at a right angle with the body. Pin it there temporarily with one pin, carefully, while you draw up the under wing to a natural position, and pin that. Put a slip of paper over both wings, pinning one end above the upper and the other below the under wing, thus holding both wings flat on the stretching board. Take out the pins first put in the wings and let the paper do the holding. Treat the opposite wings in the same way. Put as many moths or butterflies on your stretching board as it will hold, and let them remain in a dry room for two, three, or more days, according to size of moths and dampness of climate. Put them in sunshine or near a stove to hasten drying. When dry, take off the slips of paper, lift the moth out by the pin through the body, and place him permanently in your collection.—Wm. C. Prime, in N.Y. Jour. of Commerce.

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THE CLAVI HARP.

The beautiful instrument which we illustrate to-day is the invention of M. Dietz, of Brussels. His grandfather was one of the first manufacturers of upright pianos, and being struck with the difficulties and defects of the harp, constructed, in 1810, an instrument a cordes pincees a clavier—the strings connected with a keyboard.

Many improvements have from time to time been made on this model, which at last arrived at the perfection exhibited in the newly patented clavi harp. The difficulty of learning to play the ordinary harp, and the inherent inconveniences of the instrument, limit its use. It is furnished with catgut strings, which are affected by all the influences of temperature, and require to be frequently tuned. The necessity of playing the strings with the fingers renders it difficult to obtain equality in the sounds. It gives only the natural sounds of the diatonic gamut, and in order to obtain changes of modulation, the pedals must be employed. Harmonics and shakes are very difficult to execute on the harp, and—last, but not least—it is not provided with dampers. The external form of the clavi harp resembles that of the harp, and all the cords, or strings, are visible. The mechanism which produces the sound is put into motion directly a key is depressed, and acts in a similar manner to the fingers of a harpist; the strings being pulled, not struck. The clavi harp is free from all the objections inherent in the ordinary harp. The strings are of a peculiar metal, covered with an insulating material, which has for its object the production of sounds similar to that obtained from catgut strings, and to prevent the strings from falling out of tune. The keyboard, exactly like that of a piano, permits of playing in all keys, without the employment of pedals. The clavi harp has two pedals. The first, connected with the dampers, permits the playing of sustained sounds, or damping them instantaneously. The second pedal divides certain strings into two equal parts, to give the harmonic octaves; by the aid of this pedal the performer can produce ten harmonic sounds simultaneously; on the ordinary harp only four simultaneous harmonics are possible. An ordinary keyboard being the intermediary between the performer and the movement of the mechanical "fingers" which pluck the strings, perfect equality of manipulation is secured. The mechanical "fingers" instantaneously quit the strings on which they operate, and are ready for further action. The "fingers" are covered with suitable material, so that their contact with the strings takes place with the softness necessary to obtain the most beautiful tones possible.



The clavi harp is much lighter than the piano—so that it can easily be moved from room to room, or taken into an orchestra, by one or two persons—and is of an elegant form, favorable to artistic decoration. Sufficient will have been said to give a general idea of the new instrument.

It is undeniable that at the present day that beautiful instrument, the harp, is seldom played; still seldomer well played. This is attributable to the difficulties it presents to pupils. Its seven pedals must be employed in different ways when notes are to be raised or lowered a semitone; chromatic passages easy of execution on the piano are almost impracticable on the harp. The same may be said of the shake; and it is only after long and exclusive devotion to its study that the harp can become endurable in the hands of an amateur, or the means of furnishing a professional harpist with a moderate income. It is needless to point out how far, in these respects, the harp is surpassed by the clavi harp.

Vocalists who accompany themselves on the harp are forced, by the extension of their arms to reach the lower strings, and by frequent employment of their feet on the pedals, into postures and movements unfavorable to voice production; but they can accompany themselves with ease on the clavi harp.

Composers are restricted in the introduction of harp passages in their orchestral scores, owing to the paucity of harpists. In some cases, composers have written harp passages beyond the possibility of execution by a single harpist, and the difficulty and cost of providing two harpists have been inevitable. These difficulties will disappear, and composers may give full play to their inspirations, when the harp is displaced by the clavi harp.—Building News.

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THE ARGAND BURNER.

Argand, a poor Swiss, invented a lamp with a wick fitted into a hollow cylinder, up which a current of air was permitted to pass, thus giving a supply of oxygen to the interior as well as the exterior of the circular frame. At first Argand used the lamp without a glass chimney. One day he was busy in his work room and sitting before the burning lamp. His little brother was amusing himself by placing a bottomless oil flask over different articles. Suddenly he placed it upon the flame of the lamp, which instantly shot up the long, circular neck of the flask with increased brilliancy. It did more, for it flashed into Argand's mind the idea of the lamp chimney, by which his invention was perfected.

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THE SUBTERRANEAN TEMPLES OF INDIA.

During the last fifteen years Bombay has undergone a complete transformation, and the English are now making of it one of the prettiest cities that it is possible to see. The environs likewise have been improved, and thanks to the railways and bungalows (inns), many excursions may now be easily made, and tourists can thus visit the wonders of India, such as the subterranean temples of Ajunta, Elephanta, Nassik, etc., without the difficulties of heretofore.

The excavations of Elephanta are very near Bombay, and the trip in the bay by boat to the island where they are located is a delightful one. The deplorable state in which these temples now exist, with their broken columns and statues, detracts much from their interest. The temples of Ajunta, perhaps the most interesting of all, are easier of access, and are situated 250 miles from Bombay and far from the railway station at Pachora, where it is necessary to leave the cars. Here an ox cart has to be obtained, and thirty miles have to be traveled over roads that are almost impassable. It takes the oxen fifteen hours to reach the bungalow of Furdapore, the last village before the temples, and so it is necessary to purchase provisions. In these wild and most picturesque places, the Hindoos cannot give you a dinner, even of the most primitive character. It was formerly thought that the subterranean temples of India were of an extraordinary antiquity.

The Hindoos still say that the gods constructed these works, but of the national history of the country they are entirely ignorant, and they do not, so to speak, know how to estimate the value of a century. The researches made by Mr. Jas. Prinsep between 1830 and 1840 have enlightened the scientific world as to the antiquity of the monuments of India. He succeeded in deciphering the Buddhist inscriptions that exist in all the north of India beyond the Indus as far as to the banks of the Bengal. These discoveries opened the way to the work done by Mr. Turnour on the Buddhist literature of Ceylon, and it was thus that was determined the date of the birth of Sakya Muni, the founder of Buddhism. He was born 625 B.C. and his death occurred eighty years later, in 543. It is also certain that Buddhism did not become a true religion until 300 years after these events, under the reign of Aoska. The first subterranean temples cannot therefore be of a greater antiquity. Researches that have been made more recently have in all cases confirmed these different results, and we can now no longer doubt that these temples have been excavated within a period of fourteen centuries.

Dasaratha, the grandson of Aoska, first excavated the temples known under the name of Milkmaid, in Behar (Bengal), 200 B.C., and the finishing of the last monument of Ellora, dedicated by Indradyumna to Indra Subha, occurred during the twelfth century of our era.



We shall speak first of the temples of Pandu Lena, situated in the vicinity of Nassik, near Bombay. These are less frequented by travelers, and that is why I desired to make a sketch of them (Fig. 1). The church of Pandu Lena is very ancient. Inscriptions have been found upon its front, and in the interior on one of the pillars, that teach us that it was excavated by an inhabitant of Nassik, under the reign of King Krishna, in honor of King Badrakaraka, the fifth of the dynasty of Sunga, who mounted the throne 129 B.C.

The front of this church, all carved in the rock, is especially remarkable by the perfection of the ornaments. In these it is to be seen that the artist has endeavored to imitate in rock a structure made of wood. This is the case in nearly all the subterranean temples, and it is presumable that the architects of the time did their composing after the reminiscences of the antique wooden monuments that still existed in India at their epoch, but which for a long time have been forever destroyed. The large bay placed over the small front door gives a mysterious light in the nave of the church, and sends the rays directly upon the main altar or dagoba, leaving the lateral columns and porticoes in a semi-obscurity well calculated to inspire meditation and prayer.

The temples and monasteries of Ajunta, too, are of the highest interest. They consist of 27 grottoes, of which four only are churches or chaityas. The 23 other excavations compose the monasteries or viharas. Begun 100 B.C., they have remained since the tenth century of our era as we now see them. The subterranean monasteries are majestic in appearance. Sustained by superb columns with curiously sculptured capitals, they are ornamented with admirable frescoes which make us live over again the ancient Hindoo life. The paintings are unfortunately in a sad state, yet for the tourist they are an inexhaustible source of interesting observations.

The excavations, which have been made one after another in the wall of volcanic rock of the mountain, form, like the latter, a sort of semicircle. But the churches and monasteries have fronts whose richness of ornamentation is unequaled. The profusion of the sculptures and friezes, ornamented with the most artistic taste, strikes you with so much the more admiration in that in these places they offer a perfect and varied ensemble of the true type of the Buddhist religion during this long period of centuries. The picturesque landscape that surrounds these astonishing sculptures adds to the beauty of these various pictures.

The temples of Ellora are no less remarkable, but they do not offer the same artistic ensemble. The excavations may be divided into three series: ten of them belong to the religion of Buddha, fourteen to that of Brahma, and six to the Dravidian sect, which resembles that of Jaius, of which we still have numerous specimens in the Indies. Excavated in the same amygdaloid rock, the temples and monasteries differ in aspect from those of Ajunta, on account of the form of the mountain. Ajunta is a nearly vertical wall. At Ellora, the rock has a gentle slope, so that, in order to have the desired height for excavating the immense halls of the viharas or the naves of the chaityas, it became necessary to carve out a sort of forecourt in front of each excavation.



Some of the churches thus have their entrance ornamented with porticoes, and the immense monasteries (which are sometimes three stories high) with lateral entrances and facades. The mountain has also been excavated in other places, so as to form a relatively narrow entrance, which gives access to the internal court of one of these monasteries. It thus becomes nearly invisible to whoever passes along the road formed on the sloping side of the mountain. The greatest curiosity among the monuments of Ellora is the group of temples known by the name of Kylas (Fig. 2). The monks have excavated the rocky slope on three faces so as to isolate completely, in the center, an immense block, out of which they have carved an admirable temple (see T in the plan, Fig. 2), with its annexed chapels. These temples are thus roofless and are sculptured externally in the form of pagodas. Literally covered with sculptures composed with infinite art, they form a very unique collection. These temples seem to rest upon a fantastic base in which are carved in alto rilievo all the gods of Hindoo mythology, along with symbolic monsters and rows of elephants. These are so many caryatides of strange and mysterious aspect, certainly designed to strike the imagination of the ancient Indian population (Fig. 3).



Two flights of steps at S and S (Fig. 2) near the main entrance of Kylas lead to the top of this unique base and to the floor of the temples.

The interior of the central pagoda, ornamented with sixteen magnificent columns, formerly covered, like the walls, with paintings, and the central sanctuary that contains the great idol, are composed with a perfect understanding of architectural proportions.

Exit from this temple is effected through two doors at the sides. These open upon a platform where there are five pagodas of smaller size that equal the central temple in the beauty of their sculptures and the elegance of their proportions.

Around these temples great excavations have been made in the sides of the mountain. At A (Fig. 2), on a level with the ground, is seen a great cloister ornamented with a series of bass reliefs representing the principal gods of the Hindoo paradise. The side walls contain large, two-storied halls ornamented with superb sculptures of various divinities. Columns of squat proportions support the ceilings. A small stairway, X (Fig. 2), leads to one of these halls. Communication was formerly had with its counterpart by a stone bridge which is now broken. There still exist two (P) which lead from the floor of the central temple to the first story of the detached pavilion or mantapa, D, and to that of the entrance pavilion or gopura, C. At G we still see two sorts of obelisks ornamented with arabesques and designed for holding the fires during religious fetes. At E are seen two colossal elephants carved out of the rock. These structures, made upon a general plan of remarkable character, are truly without an equal in the entire world.

We may thus see how much art feeling the architects of these remote epochs possessed, and express our wonder at the extreme taste that presided over all these marvelous subterranean structures.—A. Tissandier, in La Nature.

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[NATURE.]



TIMBER, AND SOME OF ITS DISEASES.[1]

[Footnote 1: Continued from SUPPLEMENT, No, 640, p. 10222.]

By H. MARSHALL WARD.

IV.

Before proceeding further it will be of advantage to describe another tree-killing fungus, which has long been well known to mycologists as one of the commonest of our toadstools growing from rotten stumps and decaying wood-work such as old water pipes, bridges, etc. This is Agaricus melleus (Fig. 15), a tawny yellow toadstool with a ring round its stem, and its gills running down on the stem and bearing white spores, and which springs in tufts from the base of dead and dying trees during September and October. It is very common in this country, and I have often found it on beeches and other trees in Surrey, but it has been regarded as simply springing from the dead rotten wood, etc., at the base of the tree. As a matter of fact, however, this toadstool is traced to a series of dark shining strings, looking almost like the purple-black leaf stalks of the maidenhair fern, and these strings branch and meander in the wood of the tree, and in the soil, and may attain even great lengths—several feet, for instance. The interest of all this is enhanced when we know that until the last few years these long black cords were supposed to be a peculiar form of fungus, and were known as Rhizomorpha. They are, however, the subterranean vegetative parts (mycelium) of the agaric we are concerned with, and they can be traced without break of continuity from the base of the toadstool into the soil and tree (Fig. 16). I have several times followed these dark mycelial cords into the timber of old beeches and spruce fir stumps, but they are also to be found in oaks, plums, various conifers, and probably may occur in most of our timber trees if opportunity offers.

The most important point in this connection is that Agaricus melleus becomes in these cases a true parasite, producing fatal disease in the attacked timber trees, and, as Hartig has conclusively proved, spreading from one tree to another by means of the rhizomorphs under ground. Only the last summer I had an opportunity of witnessing, on a large scale, the damage that can be done to timber by this fungus. Hundreds of spruce firs with fine tall stems, growing on the hillsides of a valley in the Bavarian Alps, were shown to me as "victims to a kind of rot." In most cases the trees (which at first sight appeared only slightly unhealthy) gave a hollow sound when struck, and the foresters told me that nearly every tree was rotten at the core. I had found the mycelium of Agaricus melleus in the rotting stumps of previously felled trees all up and down the same valley, but it was not satisfactory to simply assume that the "rot" was the same in both cases, though the foresters assured me it was so.