ion, after but two specific plans. A solid, mosaic centerpiece portion will form within a cold upper air stratum and, falling earthward, acquire branching additions at some lower, warmer level. Composite crystals of this character perhaps exceed all others in beauty of design, combining into one, as they do, the two most beautiful types of snow.

It is all most marvelous and mysterious, these changing habits of growth, and this momentary shifting about of the points of maximum development. Growth ofttimes occurs in alternate order, first at the corners of the hexagon, and then at the sides. In some cases, this pendulum-like swing of outgrowth may continue from beginning to end.

But perhaps the most wonderful fact of all is the marvelously symmetrical way in which all this is accomplished. If a set of spangles or branches, or tiny hexagons or other adornments, form and grow at certain points upon any one of the six, or alternate, rays, or segments, similar or identical ones are almost sure to form at the same places and moments on all of the others, so that the balance of form is always kept unimpaired.

It appears as if the magic that does this might be, in part at least, of an electric nature, and due to the presence of tiny electric charges around their peripheries. Would not the presence at certain points, and the absence at others, of tiny electric charges, shifting momentarily about, as fresh charges collected, and causing momentary realignments in the locations of the several charges, stimulate growth at certain points and retard it at others? It seems worth while tentatively to advance this theory, as a possible explanation of these perplexing mysteries. But it is a fascinating mystery this, that the crystals assume such a marvelous diversity of form, though forced by the crystallographic law under which they come into being to assume always the hexagonal form. Six rays or parts, there always are, yet what an amazing variety these parts exhibit among themselves. Individual crystals of the open, branching variety, differ one from another, in the shape, size or thickness of their primary rays, and these rays in turn, in the number, size or shape, of the secondary branches that

they possess. Those of solid tabular form differ as to their layers, or segments, and in the number and arrangement of the air tubes and shadings within them. Similarly those of a quasi-open formation vary in individual cases, in their spangles, the tiny hexagons composing them, as well as in the way in which these are combined with each other, or with rays, and arranged around the central nucleus. Yet in innumerable cases the crystals assume, at some one or more stages of growth, identical forms and outlines. It often happens that their nucleii, or ultimate outlines are alike, yet it seems to be rarely the case that any two pass through a long series of such changes of form. Hence the astonishing variety.

Snow crystals are noted among crystals because they bridge over and include within themselves so much of the solvent, air, wherein they form. This remarkable habit, in connection with the multitudinous changes of form gives great richness and complexity to their interior designs, and lends endless interest to their study. The air tubes and shadings have a biographical value, for they outline more or less perfectly, transitionary forms. The air tubes are largely formed while the crystals, or parts of such, are in process of solidification, as at the moment when branch unites to branch, layer to layer, or segment to segment, and so growth may be traced through its successive stages.

The snow crystals being, in the truest sense, exquisite works of art in themselves, charmingly adapt themselves to a great variety of uses in the industrial arts, and in various other ways. These uses are steadily broadening though they and their artistic possibilities have been as yet hardly discovered or realized by artisans in general. Metal workers, and wall paper manufacturers are, however, beginning to realize their value, and there should be a great field of usefulness for them in these lines. They also seem well adapted for use in designing patterns for porcelain, china, glassware and many other things. Silk manufacturers are beginning to see their adaptability as patterns. Their value as models in the realm of pure art is also being demonstrated. Their uses as models in

schools of art, and art craft shops are steadily increasing. Only recently Dr. Denman W. Ross, lecturer at Harvard on the theory of pure design, has adopted a large number for class room use. Prof. James Ward Stimson used them to illustrate the "beauty of nature's art," in his book, "The Gate Beautiful."

Perhaps their greatest field of usefulness, however, is along other lines, as objects for nature study, and for illustrating the forms of water. They should be invaluable to the crystallographer, for they show the forms and habits of

growth of crystals in a most charming way.

Certain it is that normal and high schools, universities and museums both here and abroad, are finding them most useful in an educational way. One university alone-Wisconsin-has over one thousand lantern slides of snow-flakes.

Indeed it seems likely that these wonderful bits of pure beauty from the skies will soon come into their own, and receive the full appreciation and study to which their exquisite loveliness and great scientific interest entitle them.

F the French glassmakers continue

their present experiments to the log.

day be able to live in glass houses and throw as many stones as we like. Science is merciless, and it pauses no more at shattering old proverbs than it does of depriving boyhood of one of its chief destructive pleasures-that joyous conjunction of brickbat and window pane that has relieved the feelings of many a young savage pent up in town. The experiments have not yet progressed so far as that, but something has been accomplished in the way of making life harder for that close-pressed practitioner, the burglar.

The idea originated in Marseilles, which has troubles of its own in the way of criminal depredations. One day, a little more than a year ago, there was an apparently organized outbreak of cambrio-leurs in some of the principal streets of that city. In broad daylight, and in crowded thoroughfares, the windows of more than a dozen jewelry shops were smashed and objects of great value were successfully made way with.

Some of the thieves were captured, and some made their escape, but the lesson re

mained, to the terror of jewelers and all others who made a practice of displaying valuable goods in their show-windows.

France is a country of iron shutters. The streets of a French city after eight or nine o'clock in the evening have the appearance of a place besieged, or at least infested with robbers and marauding bands. Every shop presents a curious aspect to American eyes, with its shutter let down to cover windows and doors with a sheet of iron that sledges and crowbars could scarcely penetrate. These precautions, which are taken in similar fashion in all private houses of every kind, even to the sixth floor windows of apartment houses and the great wallcd-in residences, are partly a survival of the Middle Ages and partly a necessary resistance to the attacks of criminals, who are nowhere so bold and persistent as in France. But it was a new thing, and terrifying, not to be able to display valuables in show-windows even in broad day.

M. Maurice Nugue, a mirror-maker

of Marseilles, got the notion that glass might be made sufficiently hard and thick to withstand any ordinary attack by burglars. The idea was quickly taken up by the Compagnie de Saint-Gobain, and experiments were made in the composition of tough slabs of glass of a thickness varying from 15 to 25 millimeters and of a clear transparency. Then tests were made of the resistance of the glass under such conditions as those of the episode in Marseilles. First a pane of ordinary plate glass was struck with an iron-capped mallet, hurled from a distance of three yards. A great hole was made in the glass, suffcient, had the pane been in a show-window, to have enabled a thief to plunder the window. The experiment was then repeated with a slab of the "burglar-proof" glass. This dalle polie was 20 millimeters in thickness. It was set in a window of ordinary shop size, but was framed in iron instead of the ordinary window sash of wood. The iron capped mallet made no impression on the glass when thrown at it from a distance of first three and then six yards. After that a disk of iron weighing ten pounds was hurled at the window, and this, at the lesser distance, had no other effect than a very slight bruise or abrasion on the surface of the dalle polie, but when the distance was increased a round hole was made in the glass. But this hole was only two centimeters in diameter on the surface of the glass. It did not extend clear through the pane, and there were no radiating fractures such as usually are seen when window-glass is broken. The final test was made with an army revolver, but the glass stopped the bullets when they had penetrated to the depth of one-quarter of a centimeter.

The experiments were regarded as successful, and a number of jewelers and others have placed this glass in their show windows. As the method of manufacturing this dalle polie is considered sufficiently important to be kept secret, the manager of the Compagnie SaintGobain was compelled to deny further information on the subject. He said, He said, however, that after all thickness is the essential thing and that any tough glass

if made sufficiently thick will answer the purpose and afford protection from ordinary attacks. But to make a glass of extreme thickness without the sacrifice of perfect transparency is a somewhat expensive process, and to meet the objections of cost and unwieldiness in "burglar-proof" glass the Compagnie Saint-Gobain has been conducting experiments along other lines. The employment of a light wire mesh or net is already well-known in America as well as in Europe. But the imbedding of this wire in the glass, while it gives it great strength, deprives it of perfect transparency, and the aim of the Compagnie Saint-Gobain has been to make something of this kind available for window glass as well as for places where only the admission of light is required.

The latest result of these experiments is a window-glass varying in thickness, according as the need may be, from a quarter of an inch to half an inch, and having imbedded in it a very light wire running in parallel, transverse lines about one inch apart. These lines of wire constitute, in effect, one continuous line starting from an upper corner of the pane, and running from left to right and right to left across the window without a break. The wire is connected with a battery and carries always a light charge of electricity. It is connected at one of the lower corners with a magnet. If the window is broken, and the wire with the glass, the electric current is broken, the magnet is released and by that action an alarm bell is set ringing. This bell may be placed anywhere within the house to rouse the occupants, or high up on the outer wall to summon the police or frighten the burglar away. As it would be impossible for a burglar to put even a hand through the glass without breaking the wire, and as the glass with its wire enforcement is very difficult to break, this product is regarded as more practical even than the very thick dalle polie. And the glass is almost perfectly transparent, the lines of wire being placed sufficiently far apart to interfere very little with the observation of the objects in a jeweler's show-window, thus in no way shutting off the display.

HY do oil wells, which have sprung suddenly into

WW

life, cease almost as suddenly to pour gold into the coffers of the exploiters? Many a well's flow has been reduced to such an extent that it could no longer be pumped profitably, not on account of there being no longer oil at the base, but for the reason that the pores of the oil sands had become closed and would no longer permit of the passage of the fluid.

The great majority of oil wells are afflicted with paraffin wax, which sticks to the rock and closes the crevices and interstices and prevents the passage of the oil. This has long been the bane of the producers.

The first man yet to de

By RENE HOMER

HOW OIL WELLS ARE
REOPENED.

a. Washer to prevent escape of steam; b. steamer; c, shot cavity; d, pocket: e, boiling water to catch paraffin,

vise a successful means of overcoming this is a resident of Jamestown, N. Y., Dr. F. A. Monroe, and the invention has brought him. prominently before the oil producing world. Dr. Monroe's invention, the efficacy of which has been positively demonstrated by its use in this section of the Appa-. lachian field, means that the flowage of the wells now in operation may be materially increased, and that those in which pumping has been suspended may be rejuvenated.

The almost universal method up to this time of ridding wells of the paraffin evil has been the blasting process, which is, to say the least, crude. The use of nitro-glycerin for this purpose has always been found

WITHDRAWING THE STEAMER FROM WELL.

the outside of a disk. In the lower part of the cylinder are inserted cast-iron billets which have been heated white hot; the ends of the tubing are then plugged. plugged. At three points in the tubing, near the top, bottom and center are rows of small holes. The water from the cylinder dropped on to these heated billets generates steam which is forced up