diameters are simultaneously produced. Each blank just fits into the surrounding one, the inner blank fitting the mandrel, and each blank is given a protective coating, which may consist of milk of lime or a mixture of graphite and coal to prevent a grinding or welding together of the blanks during reduction.

Fuel grating.-A casing which is interposed between the wall and the fire bars of an inclined grate to increase the draft forms the subject of a recently issued German patent. The casing comprises. a frame-preferably made in two sections-secured to the walls by lugs in such a manner that the part nearest to the inclined fire bars is easily replaced. The frame holds the downward extended plates together by means of bridge pieces, and the upper surfaces of the frame and the plates slope down from the walls to the fire bars to keep the fuel in the middle as it slides down the grate.

Self-ignition for internal-combustion motors.—A French patent has been taken out by the De Dion-Bouton firm on a self-ignition device for internal-combustion motors. A small cylinder is fastened to the side of the working cylinder with an opening connecting the two. The piston of the small cylinder reciprocates at one-half the rate of that of the larger one; that is, for two strokes of the main piston the auxiliary piston makes one stroke. An explosive mixture is drawn into the small cylinder on its down stroke and this is compressed to such a degree on the up stroke that it spontaneously ignites and fires the charge in the working cylinder, the flame communicating by the opening referred to.

Punching and shearing machine.-A somewhat novel design of a punching and shearing machine has been put on the market by a German firm. The feature which distinguishes it from other designs is that it is cut away longitudinally on one side to allow of a broad plate being cut up the middle. It will be worth a great deal in shipyards and bridge works, for in such works plates are usually ordered in the dimensions required, and they only require a little cutting and trimming around the edges. It can hardly fail to vibrate considerably while at work. In all other respects the machine resembles other well-known makes of eccentric machines. It is made to shear plates up to 1 inch in thickness, and the shears are in a line with the longitudinal axis of the machine. The gap on the punching side is only 191⁄2 inches, and it is intended to punch 1%-inch holes through 1-inch plate. The angle-iron shear in the middle has the corner down, and is thus quite unsuitable for shipbuilders. OLIVER J. D. HUGHES,

COBURG, June 23, 1903.

Consul-General.

NEW ILLUMINATING MATERIAL DISCOVERED.

An important discovery has been made by the well-known German chemist Hermann Blau, of Bavaria. His method is to separate, by a process of rectification, the methane and hydrogen from the other constituents of oil gas, collecting the same in steel receivers subject to a pressure of 40 atmospheres, whereby he converts it into liquid form.

A comparison of the cost of the various illuminating materials is shown in a table drawn up by Fischer in his Chemical Manual (1900):

With the liquid gas made according to Blau's method, the cost is reduced to 6. 3 pfennigs (1.5 cents), including freight.

As seen from the above table, this new illuminating material compares very favorably in cost with all others. The ease with which it can be handled and the beauty of its light should make it preferable where a lighting material is wanted as a substitute for petroleum, alcohol, or acetylene.

As Blau's light is much more easily turned on or off, it is certainly more convenient. Its low cost and its beautiful color may give it preference even to the electric light. It will undoubtedly open a new field of industry and should be promptly looked into as an enterprise and investment for Americans.

On the 24th of December, 1902, a test was had for the first time to produce the liquid gas. The trial showed how practical and very simple the process of preparation was. It has since been decided to erect an oil-gas furnace and to reconstruct the rectifying apparatus in accordance with the practical observations obtained by the experiments of last December.

A new test has recently been made and shows a most marked improvement and a remarkable productive power in every respect. It was also found that by the addition of a considerable amount of tar, which is in no wise detrimental, a beautiful yellow color was given to the gas.

No 276-03-5

A test tube filled with the liquid gas needed only the warmth of the hand to cause it to effervesce. It also effervesced when poured

upon a metallic plate and on water. was formed.

Its odor is pyroligneous aromatic.

In the latter case a crust of ice

The concentration amounted

to 537 grams instead of 550 grams per liter under a pressure of 40 atmospheres. The specific gravity, when in a gaseous state, was 1.26 (taking air at 1.0); absolute weight, 1.03.

The trial whose result was so satisfactory was carried out in the Holshaeuerschen (Maschinenfabrik) Machine Works of Bavaria, built for the apparatus and which are now backing the project. JAMES H. WORMAN,

It is reported from England that a new form of automatic coupling for railway carriages and wagons has been invented. It consists of two horizontally placed hooks, one above the other, facing in opposite directions. Coupling is effected, on the cars coming together, by the hooks automatically swinging open sufficiently to enable them to clasp. Cars are doubly held together by the two sets of hooks, and it is practically impossible for them to part unless interfered with, for in the event of one breaking the other would hold. Provision is made for allowing the hooks a considerable range of motion to enable them to travel comfortably over short curves. As they face in opposite directions, the movement which might conceivably pull one set asunder would only serve to tighten the grip of the second set of hooks. The carriages or wagons are uncoupled by pulling a lever from the side of the car.

COBURG, June 25, 1903.

OLIVER J. D. HUGHES,

Consul-General.

PRESERVATION OF EGGS.

German papers state that it is possible to keep eggs fresh for any length of time by simply immersing them in a 10 per cent solution. of silicate of soda, commonly called "liquid glass." This produces. the formation of a coating which renders the eggs perfectly air-tight. The eggs so treated retain their fresh taste for many months. The best proof of the efficacy of this treatment has been furnished by the fact that such eggs, after having been kept for a whole year, were hatched, and the chickens were strong and healthy.

The preserving solution is best prepared by dissolving I pound of liquid glass in 4 quarts of cold water. The eggs are then immersed in this solution, which should be kept in a glazed earthenware vessel, where they are kept for a short time. If one of these preserved eggs is to be boiled, the shell must be first perforated in order to prevent cracking.

FRANKFORT, June 19, 1903.

RICHARD GUENTHER,

Consul-General.

GERMAN METHOD OF DRYING WOOD.

It is generally supposed that wood which has been for some length of time in a drying room, exposed to a heat of from 50° to 60° C. (122° to 140° F.), is perfectly dry and fit for use without there being any fear that it will shrink, split, or bend; but this supposition is not always correct, as even an expert woodworker may be mistaken as to whether it is perfectly dry or not, unless he knows the exact treatment the wood has received from the time when it was felled in the forest until it left the drying room.

So far it is a little-known fact that wood which has been floated in rafts or otherwise gives a more reliable joinery and building material than that which has been carried by cart or rail to the sawmill and workshop. While the wood is lying in the water its sap and albuminous and salty substances are owing to the diffusing effect exercised by the water-dissolved and come out of the pores, the water taking their places. This dissolving process, quite similar to that which takes place during the manufacture of sugar out of cane or beets, will progress more slowly at the ordinary temperature of river water-i. e., at from 12° to 18° C. (52° to 65° F.)—than it would at a higher temperature, but the length of time rafts in Germany. usually spend on their journey down rivers is entirely sufficient for this process to take place, even at an unfavorable temperature.

The salty and other substances in the wood, like albumen and wood gum, are hygroscopic-i. e., they eagerly absorb the dampness in the atmosphere, so that apparently wood which has been kept in drying rooms for a sufficient length of time is apt to become damp again in the open air unless it has, when floating down the river, gone through the above-mentioned diffusing or washing-out process.

With the better qualities of wood a secretion of the hygroscopic substances is brought about artificially in our local drying establishments with the help of a special apparatus. The boards or planks are piled up in a long iron box, with narrow spaces between; the

can escape.

lid is then tightly screwed down, so that neither water nor steam Steam is then turned into the box at a continuous pressure of 0.2 or 0.3 atmospheres, and this process is continued for from sixty to seventy-two hours, the exact length of time being determined by the hardness and density of the wood. The steam opens up the wood and kills the protoplasm which is still alive in the cells. After having been thus prepared the wood goes into a water bath, where it is kept for about a fortnight.

The drying process, as practiced here, is about as follows: The boards are loaded on a small cart, leaving small spaces between them by placing narrow strips in position. The cart is then pushed into the first drying room. The size of these rooms differs a good deal; they are mostly from 20 to 30 meters (66.45 to 84.25 feet) long, with breadth and height to correspond. The temperature is kept between 50 and 60° C. (122° and 140° F.). Steam or hot-water pipes placed on one side and underneath the flooring supply the necessary heat, fresh air being admitted from one side by openings which can be wholly or partially closed by means of slides. At times, when the fresh air does not enter fast enough, exhausters and ventilators are employed. The air, after becoming heated and passing between the layers of wood, becomes saturated with its moisture and is then forced out at the other side of the room by numerous openings or a long slit connected with the outer air by openings. leading to the roof.

In most establishments the wood, after having been in the first heating room for a sufficient length of time, is taken right into the workshop. This, however, is not the best method; it is better to have the first drying process followed by a second one in another drying room, which is heated by means of a stove extending its whole breadth, provided with fuel-usually coke-from the outside. The process is then about the following: Each board or plank that comes from drying room No. 1 is given an exact rectangular shape at one end; it is then loaded on a cart and put into the second drying room, after which the door is closed and any loose places that may become noticeable are filled up with mortar. The fire is then started and brought to a red heat, plenty of air being allowed to pass over the fuel, while the smoke is carried off by regulating outlets, which are provided underneath and beside the cart. After from fifty to sixty hours the cart is taken out and each piece of wood carefully examined as to whether it has kept the exact rectangular shape with which it was provided before being put into the heating room. Those pieces which have kept their shape may be considered as quite dry and ready for use, while the others will be once more cut rectangular at one end and put again into heating room No. 2. On being