ble, the reduction in time particularly will be welcome.

The machine is provided with 90 special characters. Geographical, geological, statistical maps and other scientific work of a similar nature, can all be done on one machine. Provision is made for the use of 125 different styles of type by as many shuttles. A shuttle, bearing its 90 different characters, may be substituted for another in a few minutes. The accompanying illustration is that of a geological map made solely with a typewriter. Where the work is complex, details will have to be filled in with pen and ink.

Mexico's Soda Lakes

NE

WEAR the Gulf of California, in Mexico, are to be found some of the most remarkable lakes in the world. These are the carbonate of soda lakes of the

from mouth to mouth has been most effective in the transmission of other contagious diseases.

Roof Skating-Rink

To

O enjoy the healthy sport of skating some 300 feet above the street level, is probably a thing very few people have heard of. For about a year and a-half, however, such a skating-rink has existed. on the roof of Philadelphia's most fashionable hotel. The Bellevue-Stratford, as it is now named, is a magnificent building eighteen stories high, which cost $8,000,000. It possesses, besides perfect comfort and luxury, the most upto-date appliances that modern technical ingenuity has produced. On top of the building is an artificial skating-rink for the convenience of guests. The rink is easily reached by elevators.

Typewriter for Maps FOR even the delicate work of map

making, the typewriting machine may be successfully used. The saving in time and money by this method as against human labor alone, is considerable. On government work where scientific reports must be completed as speedily as possi

sun, these vast expanses have the appearance of masses of snow and ice; but the glistening masses are in reality pure carbonate of soda crystals, enough to make uncounted millions of tons of soap and panes of glass. There is but one other place in the world where natural soda is found in commercial quantities, and with it artificial evaporation must be resorted to.

At the Bay of Adair, however, the evaporation is accomplished by the sun alone. All around the deposits are the

General Butler then introduced him to President Lincoln at Washington, with a view to contracting for bunting of home manufacture. At the interview, which took place just three days before President Lincoln was shot at the opera house, a specimen was submitted and approved of, and the conversation resulted in a contract being obtained.

The first flag was made from the piece submitted to President Lincoln, every star being sewn by hand, and was sent to the present owner by General Butler. On the visit of General Grant to England, when he was entertained at Brighton Pavilion, this same flag and the Union. Jack were intertwined in the dining hall. It was displayed at half-mast on the occasion of the assassination of President Garfield, September 19, 1881; and once again in Barnes, on the occasion of President McKinley's, assassination.

ever manufactured in the United States. Until an act of Congress was passed in 1866 empowering the Secretaries of War, of the Navy, and of the Treasury to enter into contracts for bunting of American manufacture, the national flags had been made in foreign countries and from foreign wool.

The owner of this curious flag, which has 37 stars, representing the number of states then existing, undertook the manufacture of bunting-which, to a certain extent was a secret-in America, with the result that a mill in Lowell was placed at his disposal and his efforts were successful.

S

Hydrogen for Balloons As a result of experiments conducted by M. George P. Jaubert, a French scientist, on the industrial preparation of calcium hydride, an important new method of manufacturing hydrogen in large quantities has been given to the world. Under the action of water, calcium hydride yields pure hydrogen just as calcium carbide yields acetylene, or oxylith gives oxygen. Jaubert suggests, therefore, the name "hydrolith," or hydrogen stone, for this new compound, which, when chemically pure, yields about 1,200 liters of hydrogen per kilogram, or approximately eight times the volume of oxygen obtainable from oxylith.

Hydrolith, in virtue of its small weight and of the streams of pure hydrogen it is able instantaneously to evolve, seems to be destined to render the highest services to aëronauts both in replenishing military balloons on land and in swelling them en route without any necessity of descending to the ground whenever the ascensional force of a balloon has become insufficient.

The Central Aëronautic Institute of Chalais-Meudon has established for military purposes three types of balloon, viz., a "colonial" balloon of 250 cubic meters' capacity, a "field" balloon of 500

cubic meters', finally a "siege" balloon of 800 cubic meters' capacity. For the transport of the hydrogen required in replenishing a field balloon, three cars and 18 horses have hitherto been needed. In addition to the inconvenience of carrying along the cumbersome outfit, there is the necessity of frequently returning to the central station of Chalais in order to recharge the tanks. All these drawbacks will disappear after the adoption of the Jaubert scheme, when the three cars with their 18 horses will simply be replaced by the water available anywhere, in addition to 500 kilograms of a chemical compound easily transported,

and supplies of which are found every

where.

Hydrolith will, moreover, greatly increase the possibilities of aeronautics. It may be transported in the place of sand ballast on board the launch. Whenever the ascensional force of the balloon decreases, the aëronaut will be able first to swell his balloon and afterwards to use the residue (which is simply limestone) as ballast-e, to throw it overboard as required. Hydrolith is already being manufactured on a large scale by French electro-chemical works.-DR. A. GRADEN WITZ.

IN

Skyscraper Tanks

IN Philadelphia there were constructed recently some huge skyscraper tanks designed for the purpose of storing grain. The old form of tank is square or rectangular; the new form is circular, offering a far greater resistance to the pressure of the contents upon its sides. Grain weighs about sixty pounds per bushel, and, being very mobile, exerts an enormous pressuresomething equivalent to a column of water of the same height. Moreover, the grain in humid weather tends to expand, and thereby greatly increases the lateral pres

sure. Great care must be taken to exclude moisture. With this end in view, the new tanks are designed with a lining of glazed tile, as well as an exterior covering of the same. In addition, iron bands, cement, and wire netting are employed.

These giant tanks are arranged pair by pair. Underneath all is a tunnel, through which grain may be delivered as occasion requires. The smooth, glasslike surface of the interior insures a smooth flow without lodgment of the

contents.

Veil for Firemen

THE "heat veil" is a German invention

designed to protect firemen from the intense heat of conflagrations. The veil,. which is made from the fibers of cane, is quite porous, and when steeped in water, will retain its moisture for a long period. It is put in use by being fastened to the ordinary brass helmet of the fire-fighter. A successful practical test has been made of the invention at Cologne.

Window that Moves A CLEVELAND, Ohio, merchant,

crowded for window-space, hit upon an ingenious method of quadrupling his room for street display. He rebuilt the window floor in such a way as to cause it to revolve like an endless platform, over a drum at each end. The rev

MOVING SHOW WINDOW.

olution is made from rear to front. The merchant dealt in aluminum goods, and some 200 of these articles are wired to the moving floor. Thus, a large, and at the same time very unusual and striking display is secured. A small electric motor, concealed below the floor, furnished the power that moves the platform.

Automatons of the Eighteenth Century AUTOMATONS have been known for

hundreds of years, for, even as early

as the sixteenth century, there was in the Cathedral of Strassburg a carved group in wood representing Samson kneeling on a lion, whose jaws he would pull open. The apogee of automaton construction, however, was reached in Paris in 1738, when the famous works of Vaucanson appeared. The Flute-Player (see cut) is the most celebrated of them all. It is said that the idea came to Vaucanson one day in the Garden of the Tuilleries while looking at the statue of a faun playing on a flute. He broached the subject to his uncle, who could see only the folly of a madman in it, and threatened him

with confinement under a lettre de cachet if he persisted. To avoid this, Vaucanson pretended to drop the matter; but three years later he took it up vigorously and his calculations were so accurate that the pieces which he had ordered from various artisans fitted together exactly. The servant who had assisted him was so overcome when he heard the harmonious tones produced by the statue, that he fell on his knees before his master, whom he considered as a kind of demi-god.

The flute-player measured five and a half feet in height, and was seated upon a square pedestal, in which a portion of the mechanism was contained; and what rendered it more attractive still, was the fact that its maker had seen fit to give

the figure the play of features characteristic of a musician playing to charm his hearers, the movements of the lips, fingers and breath being the same as that of a living man.

The principal motive power of the flute-player was a spring that drove nine sets of bellows in nests of three each, by which wind of varying intensity was produced. Separate reservoirs or tanks. were put in communication with each of the series, and these different reservoirs opened to a common pipe leading to the mouth of the automaton. The same spring drove a toothed cylinder, like that of a music box; and, according to the requirements, the projections on the cylinder automatically admitted a breath of air of greater or less intensity.

AUTOMATONS OF VAUCANSON.

Again, a series of levers served to move the fingers of the artist, while other springs opened and closed the lips, thus giving the automaton the appearance of life.

This wonderful piece of mechanism is still preserved at Vienna.

Another automaton of Vaucanson's is the Drummer or Tambourine-Player, this being a kind of a long drum which was one of the necessary accessories of the celebrated fêtes of Provence. The mechanism of this work was similar in all respects to that of the Flute-Player.

Altogether the most remarkable creation of Vaucanson was a duck, shown between the two other figures, the whole illustration being taken from an old handbill. It was capable of eating and

drinking, of paddling itself about in the water, and of uttering the familiar cry of its living fellows. In order to give In order to give this piece all the appearance of life, it was so arranged that it could move its wings, stand upon its feet, turn its neck to the right or left or stretch it out to pick up grain like a living fowl. The construction of the wings was the object of especial attention, and these were reproduced with all their cavities, articulations, and bones.

Movable Water-Motor THE accompanying illustration shows

a type of movable water-motor which is easily built, and which is very handy around a placer mine or ranch where water is available and where power for distribution or use at varying points is desired. In several western placer mines, a motor of this kind is used to operate the derrick and crane in lifting huge boulders from the diggings; also in supplying power for the mine machine shops, or any of the odd jobs where power is needed. The mechanism is very simple, and can

be constructed by any man of ordinary mechanical ability. mechanical ability. An undershot wheel, with connecting shaft and pinions as well as operating levers, is built to a strong frame and platform. A fly-wheel with belt is attached to the main shaft; and a spool and drum are also built to the frame, for use when a derrick is operated. This spool and drum may be left off where the motor is desired to supply only power by belt or shaft.

When used in placer mines, water to operate the motor is taken from the main pipe line, the connections being made by a section of fire hose. This fire-hose connection allows the motor to be moved

from one point to another, a feature that makes it very convenient in placer mines. In the operation of a derrick for lifting boulders from the diggings, and in dragging logs down a mountain-side in lumber camps, this motor is especially convenient, as well as economical, the usual method of using a steam donkey engine being many times more expensive and requiring much more attention. The mechanism is in marked contrast to the slow and laborious methods employed by miners, lumbermen, etc., in the past. -D. H. STOVALL.