For a not very large production, the small pump suffices. This has a single compressing cylinder connected directly with the piston rod, upon which acts the steam coming from the boiler, K. This pump compresses the gas to a pressure of 10 atmospheres, and is capable of storing seven cubic meters of it per hour.

The carburets of hydrogen which separate in a liquid state through the effect of the compression of the gas are retained in a cylindrical receptacle, V, which is located between the pump and the accumulators, T.

Besides the necessary safety apparatus, there is disposed in front of the condensers a special valve, N, which allows the gas to escape into the air if the retorts or the purifying apparatus get choked up.

When the oil gas is not compressed it possesses an illuminating power four times greater than that obtained from coal gas; and, while the latter loses the greater part of its luminous power by compression, the former loses only an eighth. It is this property that renders the oil gas eminently fitted for lighting cars, and it is for this reason that several large European railway companies have adopted it.

APPLICATION TO CARS.

We show in the accompanying engravings the mode of installation that the inventor has finally adopted for railway purposes. Each car is furnished, perpendicularly to its length, with a reservoir, a, containing the supply of gas under a pressure of 6 or 7 atmospheres. The gas is introduced into this reservoir by means of a valve, which is put in communication with the mouths of supply pipes placed along a platform. The pipes are provided with a stopcock and their mouths are closed by a cap. To fill the car reservoir it is only necessary to connect the mouths of the supply pipes with the valves of the cars by means of rubber tubing—an operation which takes about one minute for each car.



When it is necessary to supply cars at certain points where there are no gas works, there is attached to the train a special car on which are placed two or three accumulators, which thus transport a supply of the compressed gas to distances that are often very far removed from the source of supply.

The reservoir of each car, containing a certain supply of gas, communicates with a regulator, b, the importance of which we scarcely need point out. This apparatus consists: (1) of a cast-iron cup, A, closed at the top by a membrane, B, which is impervious to gas; (2) of a rod, C, connected at one end with the membrane, and at the other with a lever, D; (3) of a regulating valve resting on the lever, and of a spring, E, which renders the internal mechanism independent of the motions of the car. The lever, acting for the opening and closing of the valve, serves to admit gas into the regulator through the aperture, F. This latter is so calculated as to allow the passage of a quantity of gas corresponding to a pressure of 16 millimeters. As soon as such a pressure is reached in the regulator, the membrane rises and acts on the lever, and the latter closes the valve. When the pressure diminishes, as a consequence of the consumption of gas, the spring, E, carries the lever to its initial position and another admission of gas takes place. Communication between the regulator and the lamps is effected by means of a pipe, z, of 7 millimeters diameter (provided with a cock, d, which permits of extinguishing all the lamps at once, and by special branches for each lamp. The lamps used differ little in external form from those at present employed. The body is of cast-iron; the cover, funnel, and chimney are of tin; and the burner is of steatite. The products of combustion are led outside through a flattened chimney, t, resting at o on the center of the reflector. The air enters through the cover of the lamp and reaches the interior through a series of apertures in the circumference of the cast-iron bell which supports the reflector. There is no communication whatever between the interior of the lamp and the interior of the car, and thus there is no danger of passengers being annoyed by the odor of gas. By means of a peculiar apparatus, f, the flame may be reduced to a minimum without being extinguished. This arrangement is at the disposition of the conductor or within reach of the passengers. For facilitating cleaning, the lamps are arranged so as to turn on a hinge-joint, m; so that, on removing the reflector, o, it is only necessary to raise the arm that carries the burner, r in order to clean the base, s, without any difficulty.

On several railways both the palace and postals cars are also heated by compressed oil gas; and lately an application has been made of the gas for supplying the headlights of locomotives (see figure), and for the signals placed at the rear of trains. But one of the most interesting applications of oil is that of

LIGHTING BUOYS,

in which case it is compressed into large reservoirs placed on a boat. The buoys employed are generally of from 90 to 285 cubic feet capacity, affording a lighting for from 35 to 100 days.

To the upper part of the buoy there is affixed a firmly supported tube carrying at its extremity the lantern, c. The gas compressed to 6 or 7 atmospheres in the body of the buoy passes, before reaching the burner, into a regulator analogous to the one installed on railway cars, but modified in such a way as to operate with regularity whatever be the inclination of the buoy. In the section showing the details of the lantern on a large scale the direction taken by the air is indicated by arrows, as is also the direction taken by the products of combustion. These latter escape at m, through apertures in the cap of the apparatus.



The regulator, B, in the interior of the lantern, brings to a uniform pressure the inclosed gas, whose pressure continues diminishing as a consequence of the consumption. The lantern is protected against wind and waves by very thick convex glasses set into metallic cross-bars, c. The flame is located in the focus of a Fresnel lens, b, consisting of superposed prismatic rings, and adjusted at its lower part with a circle, d, while a conical ring, e makes a joint at its other extremity. This ring is held by the top piece of the lantern through the intermedium of six spiral springs, c' c''. Under the focus of the flame there is placed a conical reflector of German silver, t.

The buoy is filled through an aperture, k, in the side of the upper tube. This aperture is provided with a valve which allows of the buoy being charged by connecting it with the accumulators located on a boat built especially for this service. As soon as the gas reaches 6 or 7 atmospheres the cocks of the buoy and reservoir are closed, and the connecting tube is removed. The consumption of gas in the lantern is. 1,230 cubic inches per hour. This being known it is very easy to calculate from the capacity of the buoy how often it is necessary to charge it.

A large number of buoys on the Pintsch system are already in use.

The oil gas is likewise applicable to the illumination of lighthouses, and among those that are now being lighted in that way we may cite the one in the port of Pillau, near Koenigsberg. Several large steamers are likewise being lighted on this plan. In such an application of oil gas the management of the apparatus is very easy, and the permanence of the illuminating power of the gas gives every facility for the lighting of the boat, whatever be the duration of the trip.

Although Mr. Pintsch's process of manufacture has been but recently introduced into France, it has received a number of applications that permits us to foresee the future that is in store for it. The Railway Company of the West has contracted for the lighting of 250 first-class cars that run within the precincts of the city; the State Railways have 56 cars lighted in this way running between Nantes and Bordeaux and between Saintes and Limoges; and the Line of the East has just applied the system to 80 of its cars.

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DELICATE TEST FOR OXYGEN.

T. W. Engelmann proposes, in the Botanische Zeitung, a new test, of an extremely delicate nature, for determining the presence of very minute quantities of oxygen, namely: its power of exciting the motility of bacteria. If any of the smaller species, especially Bacterium termo, are brought to rest, and then introduced into a fluid in which there is the minutest trace of free oxygen, they will immediately begin to move about freely; and if the oxygen is gradually introduced, their motion will be set up only in those parts of the drop which the oxygen reaches. In this way Engelmann was able to determine the evolution of oxygen by Euglena and by chlorophyl granules.

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DETERMINATION OF SMALL QUANTITIES OF ARSENIC IN SULPHUR.

By H SCHAEPPI.

Ten grms. of sulphur, pulverized as finely as possible, are covered with hot water and a few drops of nitric acid digested for some time, filtered, and washed till the washings have no longer an acid reaction. Thus calcium chloride and sulphate are removed, and calcium sulphide, if present, is destroyed. The sulphur thus prepared is covered with water at 70 deg. to 80 deg., a few drops of ammonia are added, and the mixture is digested for a quarter of an hour. All the arsenic present as sulphide is dissolved, and the ammoniacal liquid is variously treated according to the degree of accuracy required. For perfectly accurate determinations the ammoniacal solution is mixed with silver nitrate, and all the sulphur present in the state of arsenic sulphide is thrown down as silver sulphide, acidified with nitric acid, filtered, and washed. The precipitate of silver sulphide is dissolved in hot nitric acid and determined as silver chloride. From the weight of the latter the arsenic sulphide is calculated. As a less accurate but more rapid method, the ammoniacal solution of arsenic sulphide is cautiously neutralized with pure dilute nitric acid and considerably diluted. It is then titrated with decinormal silver nitrate till a drop of the solution is turned brown with neutral chromate. The arsenic is easily calculated from the quantity of silver nitrate consumed. For very rough determinations it is sufficient to treat ten grms. of finely-ground sulphur with nitric acid, to extract with ammonia, and to add silver nitrate. From the intensity of the color, or the quantity of the precipitate of silver sulphide, it may be judged if the sulphur is approximately free from arsenic or strongly contaminated. The author states that, contrary to the general belief, reddish yellow sulphur is more free from arsenic than such as is of a full yellow color.

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HOW TO PLANT TREES.

By N. ROBERTSON, Government Grounds, Ottawa.

A great deal has been written and said about tree planting. Some advise one way, some another. I will give you my method, with which I have been very successful, and, as it differs somewhat from the usual mode, may be interesting to some of your readers. I go into the woods, select a place where it is thick with strong, young, healthy, rapid growing trees. I commence by making a trench across so as I will get as many as I want. I may have to destroy some until I get a right start. I then undermine, taking out the trees as I advance; this gives me a chance not to destroy the roots. I care nothing about the top, because I cut them into what is called poles eight or ten feet long. Sometimes I draw them out by hitching a team when I can get them so far excavated that I can turn them down enough to hitch above where I intend to cut them off; by this method I often get almost the entire root. I have three particular points in this; good root, a stem without any blemish, and a rapid growing tree. This is seldom to be got where most people recommend trees to be taken from—isolated ones on the outside of the woods; they are generally scraggy and stunted; and to get their roots you would have to follow along way to get at the fibers on their points, without which they will have a hard struggle to live. Another point recommended is to plant so that the tree will stand in the direction it was before being moved; that I never think about, but always study to have the longest and most roots on the side where the wind will be strongest, which is generally the west, on an open exposure.

For years I was much against this system of cutting trees into poles, and fought hard against one of the most successful tree planters in Canada about this pole business. I have trees planted under the system described that have many strong shoots six and eight feet long—hard maple, elm, etc., under the most unfavorable circumstances. In planting, be particular to have the hole into which you plant much larger than your roots; and be sure you draw out all your roots to their length before you put on your soil; clean away all the black, leafy soil about them, for if that is left, and gets once dry, you will not easily wet it again. Break down the edges of your holes as you progress, not to leave them as if they were confined in a flower pot; and when finished, put around them a good heavy mulch, I do not care what of—sawdust, manure, or straw. This last you can keep by throwing a few spadefuls of soil over; let it pass out over the edges of your holes at least one foot.

I have no doubt that the best time to plant is the fall, as, if left till spring, the trees are too far advanced before the frost is put of the ground; and by fall planting the soil gets settled about the roots, and they go on with the season.

Trees cut like poles have another great advantage. For the first season they require no stakes to guard against the wind shaking them, which is a necessity with a top; for depend upon it, if your tree is allowed to sway with the wind, your roots will take very little hold that season, and may die, often the second year, from this very cause.

All who try this system will find out that they will get a much prettier headed tree, and much sooner see a tree of beauty than by any other, as, when your roots have plenty of fibrous roots, and are in vigorous health, three years will give you nice trees.—The Canadian Horticulturist.

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THE GROWTH OF PALMS.

In a paper (Russian) recently read before the Botanical Section of the St. Petersburg Natural History Society, Mr. K. Friderich describes in detail the anatomical structures to be met with in the aerial roots of Acanthorhiza aculeata, these roots presenting a remarkable example of roots being metamorphosed into spines. Supplementing this, E. Regel made the following remarks:

Palm trees, grown from seed, thicken their stems for a succession of years, like bulbs, only at the base. Many palms continue this primary growth (i.e., the growth they first started with) for fifty to sixty years before they form their trunk. During this time new roots are always being developed at the base of the stem, in whorls, and these always above the old roots. This even takes place in old specimens, especially in those planted in the open ground which have already formed a trunk, In such cases the cortex layer, where the roots break through, is sprung off. In conservatories, under the influence of the damp air, this root formation, on which indeed the further normal growth of the palm depends, takes place without any special assistance. When the palm is grown in a sitting room, one must surround the base of the trunk with moss, which is to be kept damp, in order to favor the development of the roots. When the base of the palm trunk has almost reached its normal thickness, then begins the upward development of the trunk, which takes place more slowly in those species whose leaves grow close together than in those whose leaves are further apart. In specimens of many species of Cocos and Syagrus, whose leaves are particularly far apart, the stems grow so quickly when planted in the open ground that they increase by five to six feet in height per annum. The stem of those palms which develop a terminal inflorescence have ended their apical growth by doing so, and wither gradually, In addition to this (withering) in the case, e.g. of Arenga saccharifera, new inflorescences are developed from the original axils (Blattachseln) from above downward, so that one sees at last the already leafless trunk still developing inflorescences in the direction toward the base of the trunk. Almost all palms with this latter kind of growth develop offshoots in their youth at the base of their trunks, which shoot up again into trunks after the death of the primary trunk, if they are not taken off before. As to the structure of the palm trunks out of unconnected wood bundles, the assertion has been made that the palm stem does not grow thicker in the course of time, and that this is the explanation of the columnar almost evenly thick trunk. But careful measurements that were made for years have led Regel to the conclusion that a thickening of the trunk actually takes place, which probably amounts to an increase of about a third over the original circumference of the trunk.

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THE FUTURE OF SILK CULTURE IN THE UNITED STATES.

Report by CONSUL PEIXOTTO, of Lyons.

In my dispatch, No. 140, dated September 1, 1880, I referred to the fact that new machinery for reeling silk had been invented, which, in my opinion, was destined to be of great importance, and to make this industry extremely valuable and profitable in our country. I beg now to submit some additional observations upon this subject, and for the purpose of being definite, to entitle them

THE FUTURE OF SILK CULTURE IN THE UNITED STATES.

Silk reeling is at present accomplished by the use of appliances which differ only in detail from those in use many centuries ago, and which can scarcely be called machines, being rather of the nature of apparatus depending entirely upon the skill and knowledge of the operative for the results produced. In fact, even the most perfect of French and Italian reels bear about the same relation to automatic machinery that an old-fashioned spinning wheel does to our modern spinning machines.

Since the date of my previous dispatch upon this subject, the new reeling machine of Mr. E. W. Serrell, jr., of New York (who still continues in Lyons), has been undergoing improvement and development, and it is with the hope of facilitating the introduction and culture of silk, and of enabling our people to adopt the best means to that end, and to avoid errors which have been disastrous in the past and are likely to be extremely expensive in the near future, that I now communicate with the department, which is equally interested in securing new sources of industry and wealth for our people at home as for the promotion and extension of their commerce abroad.

It will be recollected that from about 1834 to 1839 there raged a great speculation in mulberry trees of a certain species (Morus multicaulis) destined for feeding silk worms. This speculation led to a total loss of all the time and money devoted to it, partly because of its wild and utterly unsound character, and partly because the little silk which was actually produced could not be reeled to advantage. As a result, silk culture fell into utter disrepute and for nearly a generation was scarcely thought of as a practical thing in the United States. Time, however, showed clearly where the great obstacle lay, and although many may have imagined that other difficulties led to its abandonment in 1839-40, those who have studied the matter are unanimously of the opinion that the want of reeling machinery has alone prevented the success of sericulture in those parts of the Union which are suitable for it. Believing this obstacle to be removed, it remains to set forth in a brief manner some of the points upon which, it appears to me, the successful introduction of silk raising will depend.

For the success of silk culture in our country two things are now requisite—the acquisition on the part of those about to engage in it of sound knowledge of its processes and requirements, and proper organization.

The details of the work of silk culture are of such a nature that they may be readily understood, and I apprehend that there will be little difficulty found by those who engage in it in mastering them, after some little experience. The point at which it seems to me that there is the most danger is at the very beginning.

In order to avoid delays and losses, the person who begins silk culture should have a pretty clear idea of the scale of operations which are likely to be most profitable; of the trees, or rather shrubs, which must be obtained; of the apparatus and fixtures necessary, and of the results which may be reasonably expected from the labor and expense required. All of these items will be found to vary in different parts of the country, and I fear that general rules, broad deductions, and such information as would apply under all circumstances and in all places would be extremely difficult to formulate, and too vague for practical use at any given point.

In fact, as far as information which may be considered perfectly general is concerned, I have, for the time being, only one point to put forward in addition to what has already been published in the United States, which is to repeat and show as emphatically as possible that the use of the reels at present employed for the filature of silk is entirely impracticable in our country, and that the raiser must sell his cocoons.

This has been so often said and so clearly shown that I should consider it unnecessary to repeat it had not my attention been called to the fact that the success of several people and associations in the United States in raising cocoons has again made it a temptation to endeavor to reel silk, and during the past year I have received applications from people in different States for information as to the kind of silk reel employed here which would be most suitable for use by them.

I am aware, also, that estimates have been made and published by some eminent authorities tending to show that this work could be done on a paying basis in some places in America. So far as I have seen them, however, these estimates are fatally defective in that they do not allow for differences in quality of silk reeled by competent or incompetent people, and under circumstances favorable or otherwise, but seem to assume that any silk reeled in our country would be a first rate article, and paid for accordingly.

While this might be true in isolated cases, it could not be true in general, as with present appliances the art of reeling good silk is only to be acquired and retained by years of apprenticeship and constant practice joined to a natural talent for the work. So true is this, that even in districts where the work has been largely carried on for many generations, quite a large proportion of women who try for years find it impossible to become good reelers.

Now, there is a considerable difference in price between well reeled and poorly reeled silk—a difference so great that silk not well reeled in every way is not worth as much as the cocoons from which it is derived. It is, therefore, quite a hopeless task to reel silk unless the reeler is skilled. Even if it could be done to advantage—which I do not think it could—there exists in America no means of training reelers. In Europe they are taught by degrees in the filatures, working first at the easier stages of the operations, and afterward being helped forward under the eyes and guidance of experienced operatives.

Another grave defect in the estimates alluded to is that all the profit is assumed to be paid to the reeler. This can evidently only be the case when each reeler runs her own reel, owns and cares for her own cocoons, sells her own silk, and furnishes her own capital. Now, even supposing that persons so fortunately placed as to be able to fulfill all these conditions should wish to engage in silk reeling, which is in the highest degree improbable, there exists an almost insuperable obstacle to the production of good silk except by an establishment large enough to use the cocoons of many producers.

Nearly every silk crop as raised by the individual growers contains three or four grades of cocoons, and to produce good and uniform silk, these must be separated and each sort reeled by itself, producing several grades of silk.

Without going into detail, it is enough to say that this is not practical for those who attempt to reel their own cocoons, and that for this reason, and many others, hand reels and single basins have been nearly abandoned even in Italy; the women finding so much difficulty that they prefer to sell their cocoons and work in large establishments where the work is done to more advantage.

It is evident, therefore, that, from the estimates made, there should be a considerable deduction for poor workmanship, and another for use of capital, organization, selling expenses, superintendence, insurance, repairs, deterioration, etc. In fact, I do not see in what way the reeling of silk in the United States, by the ordinary method, could be made to bear a much higher charge for labor than that borne by European filatures, which barely pay with labor at one franc per diem of thirteen hours.

To be able, then, to reel silk by the ordinary reels, it would first be necessary to find a sufficiency of highly skilled operatives willing to labor in a factory thirteen hours per day for twenty cents each. I sincerely believe and hope that this can never be done. I have enlarged somewhat upon this difficulty for the purpose of showing that the growers, or at any rate individual growers of cocoons, should not attempt to do the reeling, but by no means with an idea of discouraging the raising of silk worms, which is and should be an entirely separate matter. To use a rough comparison, I should esteem it as wasteful, even if possible, for each grower to attempt to reel his own cocoons as for each farmer to grind his own wheat upon his farm and endeavor to sell the flour.

It is, therefore, clear that the object of the sericulturist should be to raise and market as good a crop of cocoons as possible to the best advantage, and with the least possible expense and risk.

After what has been said, it may be very properly asked, if, seeing that the hopes which have been entertained of reeling by the usual method have proved fallacious, and as no radically new system of raising silk worms is under consideration, it is not very possible that all hopes of profit from rearing the worm may prove fallacious also.

In fact, not only has the question been asked, but an argument of great apparent strength and much plausibility has been formulated and extensively circulated, tending to show that the difficulty of cheap labor, which it has been shown stood in the way of reeling without improved machinery, will make the raising of cocoons also a hopelessly unprofitable task.

Briefly summarized, this argument may be stated as follows:

First. To raise silk worms to advantage much time and attention are required.

Second. Time and attention are more costly in the United States than in other countries.

Third. Consequently, cocoons can be more cheaply raised in other countries than in the United States.

Fourth. The United States possess no special advantages as a market for cocoons, and therefore they must be sold as cheaply as elsewhere, and the labor costing more, there is less profit.

Fifth. The profits made by raisers in Europe are not very great, and as they would be less in the United States, it is not worth while to try to raise cocoons in that country.

It must be acknowledged that upon the surface this all appears to be very sound and almost unanswerable, but I hope to be able to show that there is in reality not the slightest real foundation for the conclusion to which this argument points.

Taking the points cited in order, I would say, as regards the first and second, that although labor and time are required to raise cocoons, I am convinced that the labor and time of the kind necessary will not be found more expensive in our country than in Europe, for the following reasons:

The work is a home industry. It can be carried on without severe manual labor except for a few days, at the end of the season, when large crops are raised.

Now, nothing is better known than that there exists in many of our States an enormous number of wives and daughters of country people of a class entirely different from any to be found elsewhere, except, perhaps, to a limited extent, in England. I refer to the "well-to-do" but not wealthy agricultural and manufacturing classes in small villages.

One or two generations ago the farmers' and mechanics' wives and daughters found plenty of work in spinning, weaving, dyeing, cutting, and making the linen and clothes of the family. This has entirely ceased as a domestic industry with the exception of the "sewing" of the women's clothes and men's underwear. As a consequence, the women of the family are condemned to idleness, or to the drudgery of the whole household work.

Upon a proper occasion I think that much might be said of the evils and dangers which are likely within a short time to arise from the fact that perhaps a large majority of American women find themselves, because of the present organization of society and industry, almost unable to contribute to the family income except by going away from home, or in doing the most menial and severe labor as household workers from one end of the year to the other. I shall at present, however, only point out that in hundreds of thousands of homes in the country an opportunity of gaining a very moderate sum in addition to the present income by the expenditure of some weeks of care and light work would be hailed as a Godsend, and that, too, in families where the feeling of self-respect and the desire to keep the family together are far too strong to permit the women to go away from home in any way to earn money.

Let any one who doubts this consider the dairy work and similar industries, and try to calculate how much per diem the women thus occupied at home gain in money. It may be said with entire accuracy that, as a rule, anything in which the women can engage at home, by which something may be earned, will in general be regarded as net profit through out many sections of the land. In the silk districts of Europe, agricultural machinery is very much less employed than with us, and in general every woman who can possibly be spared from other work is a field laborer and valuable as such. So that time taken for raising silk must be deducted from her other productive work and charged to the cost of the silk crop. I think that there can be no doubt that this one fact is quite sufficient to make the question of the cost of caring for the worms really as much in favor of the United States as at first glance it appears to be the other way; it being the case that in our country many who would be glad to do the work have spare time to give to it, whereas in Europe every hour that is given to silk worms would otherwise be spent in the field.

In the South there are very large masses of inhabitants who are unable to work in the fields, both men and women, and who would also find in a yearly crop of silk worms a very comfortable addition to their yearly gains, and one which could be derived from time not otherwise convertible into money. Land is very much dearer, and taxes are higher in the European silk districts than with us, and every little crop of cocoons has to pay its share, which adds a considerable percentage to its cost.

The buildings possessed by peasants and used for the raising of silk worms are, in general, small, close, and miserable. Throughout America the roomy barns which are empty at the cocoon season, will, with little preparation, be much preferable, and enable the raisers to work to very much better advantage.

In Europe diseases of several kinds have become more or less prevalent, and in some cases have diminished the production of whole districts.

Notwithstanding the fact that many experiments have been made in America, and in Georgia particularly, and silk has been raised continuously for over a century, these diseases (maladies des vers a soile) have never made their appearance.

The people of our country are, as a rule, much better educated than those in Southern France and Italy, and will undoubtedly use their intelligence in such a way as to derive a benefit from it, and economize their labor by proper appliances, etc.

Taking all these facts into consideration, I am convinced that that there will be no difficulty in raising cocoons for the same cost in labor in the United States as in Europe, and I am inclined to think that the work can be much more cheaply done.

It is true that the United States is not an especially good market for cocoons; in fact up to this time there has been scarcely any market at all for them; but with the organization of the industry and the introduction of reeling machinery, the market will be at least as good there as elsewhere. As to whether it will be "worth while" for our people to raise silk worms, I would say that though the amount of money to be paid by any one family is certainly not very large, it is nearly all clear profit, and under the circumstances which I have above pointed out, and which exist so generally, I am sure that the sum to be realized will be regarded as very important by a vast number of people. As in other points, it is extremely difficult to make any exact estimates on such a subject which would be generally applicable to a country so large and so various in climate, soil, and social habit as ours. I am inclined to think, however, that were the members of an average family, under average circumstances, to raise a crop of cocoons, the amount which could be advantageously reared should produce, according to circumstances, from seventy-five to two hundred dollars. Scarcely any "paying" result can be hoped for, however, without more or less organization of the work, as sericulture is an industry which is very sensitive to the evils of a want of proper co-operation among those who carry on its various processes. After some reflection, I am of the opinion that individual growers will have great difficulty in selling cocoons if they are isolated from others, and I therefore doubt the wisdom of encouraging sporadic and ill-directed efforts, which, however well meant and earnestly pursued, are much more apt to end in disappointment, discouragement, and discredit to the newly developing industry than in anything else. It seems to me to be neither wise nor fair to furnish estimates of returns, which presuppose an organization of the industry, without mentioning the difficulties which must be encountered where the organization is lacking. The great difficulty is in selling the cocoons after they are raised, and this can only be practically overcome by such a development of the culture as will result in the production, within the limits of a given neighborhood, of sufficient quantities of cocoons to make it practicable to prepare and forward them to market. It is as well known as any other fact in trade, that small transactions are much more costly in proportion than large ones, and this general rule is especially applicable to the cocoon market. The product of two or three isolated families in the interior of our country could not be marketed to advantage. Whereas, were several hundreds engaged on the work in the same vicinity the charge of marketing their joint crop would be only a small percentage of its value.

Silk raising is the work of an organized people, and before it can become successful in our country must possess proper channels for its trade, just as much as wool, or cotton, or wheat. The machinery of this organization, however, need not be either complicated or expensive. What is required is a system of nuclei in towns or large villages, which may serve as centers of information and as gathering receptacles for the crops of surrounding producers.

The details of organization must be left, and I think may safely be left to the good sense of the people of different sections, who will work out the problem in different ways, according to their different circumstances. Even were the need of organization not made evident to those undertaking sericulture in the beginning, it would soon become so, as it has, in fact, in several parts of the country. I have therefore deemed it proper to call attention to this matter, on the principle that a "stitch in time saves nine." I am informed that there exist already in the United States several associations devoted to acquiring and disseminating knowledge of the art of sericulture. This is a very great step in the right direction, and cannot be too heartily commended. If conducted with prudence and wisdom these societies will be of great service, and I would respectfully suggest that any encouragement which the government may think proper to afford would in all probability be extremely useful and profitable to the country in the future. Provided, always, that such societies are really devoted to the dissemination of information and the careful organization of the industry, and are not merely visionary and impractical cultivators of misapplied enthusiasm.

It would, I think, be of importance so far as possible, to direct the attention of county and State agricultural societies, "village improvement clubs," and in general the intelligent and careful portion of our rural population to this matter. It is beyond doubt that the time when sericulture can be begun and carried on profitably in our country has arrived. Its successful introduction would result in a very important yearly revenue and increase in the public wealth, for I think that within a comparatively few years it could be made to be worth at least fifty or sixty millions of dollars per annum, and perhaps much more. This, however, is a less advantage than the fact that by supplying a new home industry it would do much toward conserving home ties and interests, and thereby help to strengthen and perpetuate good morals and home living among our people.

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THE HIBERNATION OF ANIMALS.

"Don't black bears sleep through the winter?" questioned the writer of an attendant who was dealing out mid-day rations of bread and milk at the park.

"That's the general impression," was the rejoinder, "but we have never noticed any attempts at hibernation here. Bears are unusually lively during the cold months, and demand their food as regularly as do the lions and other feline animals. I don't know that any observations of value on this question have ever been made on animals in confinement. I have had some experience with outside animals, and a great many go through what is called a winter's sleep; and in warm countries there is what might be called a summer sleep. Bears begin in the fall to look out for a soft nest; and if it's possible for them to eat more at one time than another they do it then, and when the cold weather sets in they are fat and in prime condition. According to some authorities, the fat produces the carbon that in some way tends to induce somnolency. The stomach of a bear at this time becomes empty, and naturally shrivels or draws into a very small space, and is rendered totally useless by a substance called 'tappen' that clogs it and the intestines; this is formed of pine leaves and other material that the animal takes from ants' nest and the trunks of trees in its search after honey. They lie asleep in this condition for about six months, generally snowed in; but you can tell the place, as the heat of the bear, what there is left, keeps an air hole up through the snow. The bear seems to live on its fat, the tappen preventing its too rapid consumption; and if you run across them during this time—even along in March just before they wake up—they are about as fat as when they went in. I have taken a slice of fat from a black bear six inches thick—regular blubber. I remember," continued the man, "one winter I was 'log hauling' in the western part of this State. We had our eyes on a big tree, and one morning when it was about ten degrees below zero I tackled it to warm up. I hammered away for about five hours at it and finally started her, and over she came—slowly at first, and then as if she was going right through. The snow was nearly three feet deep, and as the tree struck it flew up for about twenty feet and half blinded me, and when I came to there was the biggest black bear I ever saw standing along side of me, looking about as mixed as I did. I had lost my ax, and the first move I made she started, and on taking a look I found that she had a nest in the trunk and had probably turned in for the winter. It was about twenty feet from the ground, and was built with moss, leaves, and all kinds of truck, and as warm and as snug as you please—a good place to spend a winter in."

The brown and polar bears have the same habit of lying up for the winter. An Esquimau informed Captain Lyon that in the first of the winter the pregnant bears are always fat and solitary. When a heavy fall of snow sets in the animal seeks some hollow place in which she can lie down, and remains quiet while the snow covers her. Sometimes she will wait until a quantity of snow has fallen and then digs herself a cave; at all events it seems necessary that she should be covered up by the snow. She now goes to sleep and does not wake until the spring sun is pretty high, when she brings forth two cubs. The cave by this time has become much larger by the effect of the animal's warmth and breath, so that the cubs have room enough to move, and they acquire considerable strength by continually sucking. The dam at length becomes so thin and weak that it is with great difficulty she extricates herself, which she does when the sun is powerful enough to throw a strong glare through the snow which roofs the den. Then the family comes out, and will take anything that comes along in the way of food. During the long sleep the temperature of the bear's blood is reduced to almost that of the surrounding air. The power of will over the muscles seems to be suspended, respiration is hardly noticeable, and most of the vital functions are at a complete standstill—the entire body sleeping, as it were. The male grizzly bear never hibernates. The young and the females, however, build nests, one of which measured ten feet high, five feet long, and six feet wide.

Bats are great winter sleepers, and in most of the known caves they can be found during the cold months clinging to the walls and to each other. During hibernation their respiration ceases almost entirely, and only the most careful use of a stethoscope can reveal it. The air that has surrounded numbers of them has been carefully examined and not the slightest evidence found of its having been breathed; and, stranger yet, they can exist in this condition in gas, that, were they awake, would prove instantly fatal. A machine has been invented to examine these and other animals while in this condition. A delicate index records the slightest pulsation, while a thermometer shows the rise and fall of the temperature at every moment during the period; and by an arrangement of the wing, the circulation of the blood is recorded. A more delicate experiment can hardly be imagined, as a strong breath, a sneeze, or a footfall will cause the subject of the experiment to recover enough to respire several times; and the effect of this on the machine can be imagined when it is known that though, while in this condition, they produce no effect upon the oxygen of the air about them, they consume when respiring more than four cubic inches of oxygen an hour.

The common marmot is a great underground sleeper. They build large storehouses, sometimes eight feet in diameter, and from the latter part of September to April they lie in them, and, like the bears, give birth to their young during this period.

The dormouse is a remarkable sleeper. Even in their ordinary sleep they can be taken from the nest and handled without waking them. Toward winter they acquire a great deal of fat, and stow away a vast amount of provision around about their nest, and then go to sleep within; but they rarely awake to use this food unless a very warm period comes around before the regular breaking up of cold weather.

The hedgehog is a sound winter sleeper, and has been the subject of an infinite number of experiments while in this condition. One experimentalist, believing that cold was the cause of their curious condition, surrounded one with a freezing mixture, and froze it to death. By increasing the cold about another that was already hibernating, it was made to wake up; and walked off.

If an animal is suddenly decapitated while in this hibernating condition, the action of the heart is not affected for some time, a second life seeming to outlive the one taken. An experiment has been made in which the brain of the sleeper was removed, then the entire spinal cord, but for two hours hardly any change was noticeable upon the action of the heart; and a day after that organ contracted when touched by the operator.

The writer has the winter nest of a family of ants. A piece of fence rail was found beneath an old pile of boards and brought into a warm room for the sake of a rich fungus growing upon it, and several hours after the table and chairs were found to be covered with ants. Where they came from was a mystery, until the old rail was accidentally jarred and a number fell from it. A section was cut down through it, and the winter home of the tribe destroyed—probably the work of weeks, perhaps months. The interior of the wood was completely riddled by tunnels and passages, some being large and holding several hundred ants, while others contained only a few. In some of the interior passages the ants had not been affected by the heat, and were packed in great masses and evidently fast asleep; they soon recovered, however, and walked off slowly in different directions, as if wondering if an earthquake or spring had come.

A great number of insects go through a period of hibernation, especially spiders. The young of the latter are often covered by the parent; first, by coarse strings of silk, as if to hold them in place, and then by a white, silvery web worked over them, which forms probably a sure protection from wind and weather.

The writer has a cherry-stone in which is coiled up an insect, best known as the sowbug. A squirrel had probably eaten out the meat and opened the way, and in this snug retreat we found the little hibernater snugly rolled up, as is also its habit when alarmed. The mouth of the hole was stopped by black soil, but whether from accident or by the animal itself we could not tell.

Some fishes and reptiles are hibernaters. Frogs and toads sleep out the winter at the bottom of ponds or in holes in the ground. Tree toads, if kept in a cage in the winter and provided with soil, will endeavor to cover themselves with it, showing how strong the instinct or habit is. Some fishes are so insensible to heat or cold that when in this condition they can be frozen and carried for a number of days and then be brought back to an active condition. The pond snail passes into a winter sleep as soon as the temperature of the water is below 14 deg. Cent., that is, they will not digest food or grow until the temperature of the water is at least up to 15 deg. Cent. Those who have watched the Harlem River from McComb's Dam Bridge cannot have failed to notice the curious appearance of the muddy shores of the river and creeks at low tide. If the sun shines brightly, the dismal beach seems to quiver and scintillate in a most beautiful manner, reflecting the light like so many diamonds. If we draw nearer, this shore is seen to be entirely covered in places with little snails, that, left by the tide, are forging through the mud to regain the water, and the sunlight striking on them is reflected by the glass-like secretion with which they are covered, producing the curious effect noticed. This could be seen in the warm months, but now, not a snail of the countless millions can be seen. They have gone down in search of "hard-pan," there to hibernate until next April. The land snail (Helix pomatia) sleeps four months during the year, and does not throw off the calcareous lid that protects it during this time until the day temperature has reached 12 deg. Cent. Prairie dogs feel the effect of temperature as low as this.

In Cuba reptiles hibernate between 7 deg. and 24 deg. Cent., according to the species. In warmer countries, snakes, lizards, frogs, etc., fall into a state called chill coma that precisely resembles winter sleep, but their temperature is far above that at which hibernating animals of the north are still active. The state of hibernation is not the direct result of an extreme of heat or cold, but rather is caused by a departure from the optimum. In the snail its normal temperature is about the same as the water, and being a poor heat producer it is not surprising that when the water grows colder the animal is forced to succumb; but it is a remarkable fact that warm-blooded animals like many of the above-mentioned, whose bodies are maintained by internal processes at a high temperature of 26 deg. to 38 deg., are incapable of resisting the lowering influence of cold. The fall in temperature in some is wonderful; as an example, the high body temperature of warm-blooded animals may be said to oscillate between 36 deg. and 43 deg. Cent. (this includes man). Experiments made with the zizel show that during hibernation this animal's temperature is only 2 deg. Cent., the lowest known; and a thermometer introduced into the animal indicated the same, showing that warm-blooded animals in hibernating become truly cold blooded animals. If a rabbit's temperature reaches 15 deg. Cent., it will die. The germs of bryozoa or of the fresh water sponges resist any amount of cold, but the full grown forms die at the first cold turn. Insects are destroyed, but their eggs live, though of the greatest possible delicacy. Salmon eggs have been carried from this State to Australia, and there hatched. In fact, some animals live in the ice, as the glacier flea and several others.

As it is not the direct result of extremes of heat or cold that produces sleep, neither is the awakening from hibernation directly caused by a rise of temperature. In experiments made upon weasels, which are sometimes caught asleep, one came to life in about three hours, during which the temperature of the room remained the same as it had been during the entire hibernation, viz., 10 deg. Cent. In another weasel, during the awakening, the body temperature rose very rapidly—and more so in the second part of the period than in the first. In the first hour and fifty-five minutes of the awakening the body temperature rose 6.6 deg. Cent, and in the following fifty minutes it rose 17 deg. Cent. This remarkable increase took place without any vigorous movements on the part of the weasel. Even its breathing showed no increase in proportion to the rise. These cases show that though, at certain seasons, animals relax as it were and lie dormant, and recover, seemingly at the will of the weather, yet, in point of fact, the rise and fall of temperature has no direct effect upon them. The cause is an internal one, awaiting discovery.—C. F. HOLDER, in Forest and Stream.

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What is described as the largest steel sailing ship afloat was lately launched at Belfast, Ireland. It registers 2,220 tons, and has been named the Garfield. It will be employed in the Australian and California trade.

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THE TIDES.

London Nature, in a recent issue, says: From a scientific point of view, the work done by the tides is of unspeakable importance. Whence is this energy derived with which the tides do their work? If the tides are caused by the moon, the energy they possess must also be derived from the moon. This looks plain enough, but unfortunately it is not true. Would it be true to assert that the finger of the rifleman which pulls the trigger supplies the energy with which the rifle bullet is animated? Of course it would not. The energy is derived from the explosion of gunpowder, and the pulling of the trigger is merely the means by which that energy is liberated.

In somewhat similar manner the tidal wave produced by the moon is the means whereby a part of the energy stored in the earth is compelled to expend itself in work. Let me illustrate this by a comparison between the earth rotating on its axis and the fly-wheel of an engine: The fly wheel is a sort of reservoir, into which the engine pours its power at each stroke of the piston. The various machines in the mill merely draw off the power from the store accumulated in the fly-wheel. The earth is like a gigantic fly-wheel detached from the engine, though still connected with the machines in the mill. In that mighty fly-wheel a stupendous quantity of energy is stored up, and a stupendous quantity of energy would be given out before that fly-wheel would come to rest. The earth's rotation is a reservoir from whence the tides draw the energy they require for doing work. Hence it is that though the tides are caused by the moon, yet whenever they require energy they draw on the supply ready to hand in the rotation of the earth. The earth differs from the fly-wheel of an engine in a very important point. As the energy is withdrawn from the fly-wheel by the machines in the mill, so it is restored thereto by the power of the steam engine, and the fly runs uniformly. But the earth is merely the fly-wheel without the engine. When the work by the tides withdraws energy from the earth, that energy is never restored. It, therefore, follows that the earth's rotation must be decreasing. This leads to a consequence of the most wonderful importance. It tells us that the speed with which the earth rotates on its axis is diminishing. We can state the result in a manner which has the merits of simplicity and brevity. The tides are increasing the length of the day. At present, no doubt, the effect of the tides in changing the length of the day is very small. A day now is not appreciably longer than a day a hundred years ago. Even in a thousand years the change in the length of the day is only a fraction of a second. But the importance arises from the fact that the change, slow though it is, lies always in one direction. The day is continually increasing. In millions of years the accumulated effect becomes not only appreciable, but even of startling magnitude.

The change in the length of the day must involve a corresponding change in the motion of the moon. If the moon acts on the earth and retards the rotation of the earth, so, conversely, does the earth react upon the moon. The earth is tormented by the moon, so it strives to drive away its persecutor. At present the moon revolves around the earth at a distance of about 240,000 miles. The reaction of the earth tends to increase this distance, and to force the moon to revolve in an orbit which is continually growing larger and larger. As thousands of years roll on, the length of the day increases second by second, and the distance of the moon increases mile by mile. A million years ago the day, probably, contained some minutes less than our present day of twenty-four hours. Our retrospect does not halt here; we at once project our view back to an incredibly remote epoch which was a crisis in the history of our system. It must have been at least 50,000,000 years ago. It may have been very much earlier. This crisis was the interesting occasion when the moon was born. The length of the day was only a very few hours. If we call it three hours we shall not be far from the truth. Purhaps you may think that if we looked back to a still earlier epoch, the day would become still less, and finally disappear altogether. This is, however, not the case. The day can never have been much less than three hours in the present order of things. Everybody knows that the earth is not a sphere, but there is a protuberance at the equator, so that, as our school books tell us, the earth is shaped like an orange. It is well known that this protuberance is due to the rotation of the earth on its axis, by which the equatorial parts bulge out by centrifugal force. The quicker the earth rotates the greater is the protuberance. If, however, the rate of rotation exceeds a certain limit, the equatorial portion of the earth could no longer cling together. The attraction which unites them would be overcome by centrifugal force, and a general break up would occur. It can be shown that the rotation of the earth, when on the point of rupture, corresponds to a length of the day somewhere about the critical value of three hours, which we have already adopted. It is, therefore, impossible for us to suppose a day much shorter than three hours.

Let us leave the earth for a few minutes and examine the past history of the moon. We have seen the moon revolve around the earth in an ever-widening orbit, and consequently the moon must, in ancient times, have been nearer the earth than it is now. No doubt the change is slow. There is not much difference between the orbit of the moon a thousand years ago and the orbit in which the moon is now moving. But when we rise to millions of years, the difference becomes very appreciable. Thirty or forty millions of years ago the moon was much closer to the earth than it is at present; very possibly the moon was then only half its present distance. We must, however, look still earlier, to a certain epoch not less than fifty million of years ago. At that epoch the moon must have been so close to the earth that the two bodies were almost touching. Everybody knows that the moon revolves now around the earth in a period of twenty-seven days. The period depends upon the distance between the earth and the moon. In earlier times the month must have been shorter than our present month. Some millions of years ago the moon completed its journey in a week instead of taking twenty-eight days as at present. Looking back earlier still, we find the month has dwindled down to a day, then down to a few hours, until at that wondrous epoch when the moon was almost touching the earth, the moon spun around the earth once every three hours.

In those ancient times I see our earth to be a noble globe, as it is as present. Yet it is not partly covered with oceans and partly clothed with verdure. The primeval earth seems rather a fiery and half-molten mass, where no organic life can dwell. Instead of the atmosphere which we now have, I see a dense mass of vapors in which perhaps, all the oceans of the earth are suspended as clouds. I see that the sun still rises and sets to give the succession of day and of night, but the day and the night together only amounted to three hours, instead of twenty-four. Almost touching the chaotic mass of the earth is another much smaller and equally chaotic body. Around the earth I see this small body rapidly rotating, the two revolving together, as if they were bound by invisible bands. The smaller body is the moon.

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DRILLING GLASS.

The Revue Industrielle gives the following method of drilling holes in glass: First, prepare a saturated solution of gum camphor in oil of turpentine. Then take a lance-shaped drill, heat it to a white heat, and dip it into a bath of mercury, which will render it extremely hard. When sharpened and dipped into the above-named camphor solution, the tool will enter the glass as if the latter were as soft as wood. If care be taken to keep the spot being drilled constantly wet with the solution, the operation will proceed rapidly, and there will rarely be any need of sharpening the tool.

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A catalogue, containing brief notices of many important scientific papers heretofore published in the SUPPLEMENT, may be had gratis at this office.

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