Will the Iron Last? DURING the year 1905, according

to a leading German authority, the world's production of iron amounted to 53,997,965 tons, of which the United States produced 22,992,380 tons. No complete statistics for 1906 are as yet available, but during that year the United States increased its output to a very considerable extent, and in other countries the increase of production was not insignificant. The great iron producing nations, in their relative rank, are: the United States, Germany, England, and France. Canada, though at present only tenth on the list, is rapidly coming for

COURTESY SCIENTIFIC AMERICAN, N. Y.

LAMP THAT BURNS LUSOL, A NEW ILLUMINANT.

ward and doubled her output of 1904 in 1905.

The world's total visible supply of iron, according to a noted Swedish expert, is ten billion tons, although it is believed by some authorities that this estimate is somewhat low, the assertion being made that there are four billion tons in unlo

cated mines in the United States. Even assuming, however, that there are in existence fifteen billion tons of iron, it is obvious that the supply will be totally exhausted if the production increases year by year as it has in the past, within a comparatively short time. When asked what the world will do when this comes about, most engineers answer, "economize the iron, using it only for engines, and other things absolutely necessary, and use concrete for bridges, buildings, and a thousand other things for which iron is now used.

New High-Power Light LUSOL, a new illuminant; has no

chemical individuality, but is merely a commercial name. It closely resembles acetylene. To prevent the deposit of black smoke a special lamp was devised. It is not only a lamp, but a small distillery. As lusol is very volatile and highly inflammable, this lamp had to be very carefully made to prevent leakage. Even should the lamp be overturned, not the slightest breath of the illuminant can escape. Below the burner is a central tube, reaching to the base of the receiver. Herein a tightly packed wick is fixed. The tube is closed at the top, thus effectually preventing the wick from emerging. The wick itself is not lighted. Its power of capillary attraction merely is used to draw the lusol to the distillery compartment. It is the vapor which burns.

The only communication between the exterior and interior of the lamp is an orifice so minute that a fine needle hardly can enter. This opening is so nicely adjusted that it allows just enough vapor to escape to ensure a sufficient quantity of air to keep the flame burning. The lusol lamp heats as well as illuminates. The lamp is promptly extinguished by the closing of the minute orifice.

The advantages of the lusol lamp lies in its great illuminating power and in its

cheapness. It can be left burning a whole day at a cost of about five cents. For outlying villages and farm houses this form of lamp should be particularly valuable.

A Search-Light Auto A MOTOR vehicle of an exceptional

type has been built to the order of the Volunteer Tyne Division Royal Engineers of England. Since completion this outfit has been through severe trials and has been a distinct success. During recent naval manoeuvers it rendered special service at Portsmouth and Stakes Bay and was also useful for field work at Salisbury during night attacks. Its usefulness has also been fully demonstrated at Aldershot, where England's famous military camp is situated, and it is now stationed at Cliffords Fort, North Shields, the headquarters of the Tyne Division of the Royal Engineers.

The chassis is built up of steel channels with the necessary cross members of the same dimensions. The petrol supply is carried in two large circular tanks, one at each side of the car, and so arranged in duplicate, as is the whole outfit, that the light can be kept running and one tank filled while the other is in use. This same principle applies to accumulators,

Water Pipes Suspended

ONE of the most remarkable bridges in America spans the Skagit River in the state of Washington. A town near the river depends for its water supply upon a number of springs in the mountains on the other side of this stream. The water is carried to the town in an iron pipe having an opening about six inches in diameter. The question arose how to carry this conduit across the river. To build an ordinary bridge was far too expensive, owing to the width of the stream, and it was found impossible to lay the pipe on the river bed because the rapid current would probably break it. Finally it was decided to make a sort of suspension bridge. A tower of strong timber was erected on each bank and a wire cable stretched across from the top of one

tower to the top of the other. Then the lengths of pipe were fastened securely to this cable by smaller cables as fast as the lengths were joined together. At each end of the cable an elbow was set into the pipe line and connected with other lengths reaching to the ground. When the work was finished, two wires were stretched across above the pipe and thus a sort of footway was made over the river, which is frequently used by the lumbermen in the vicinity. This novel aerial conduit has been in use for several years and although filled with water most of the time has not yet broken. The photographs show one end of the conduit and tower, also a section of it above the river.

Springy Roadbed INTERESTING experiments have recently been made in Switzerland with a new roadbed material which, in use, has a remarkable elasticity, and for which many advantages are claimed.

The materials used in the preparation of the macadam are gravel and tar; the gravel of 30 to 50 millimeters fineness. This gravel is heated and subjected, in a revolving drum, to the action of liquid

tar, so that each particle becomes covered with a fair coating.

This tarred gravel is then allowed to stand in heaps, protected from the weather, for eight or ten weeks. It is asserted that during this period fermentation occurs which causes the tar to penetrate the pores of the gravel and in this way lessen the formation of dust. This material must be applied to the roadbed in absolutely dry weather, and no foreign. matter allowed to become mixed with it. A steam roller is used to smooth it out, and no water must be used in this rolling. The cost of preparing the macadam is small, 44 pounds of tar being sufficient for 1 cubic meter of gravel, or, if limestone is used, for 55 pounds.

of travel. Some of these chairs are placed directly over the boiler. In making their inspections the railway officials have their private coaches attached to the engine, retiring from the observation car when wearied.

Cloth To Stop Bullets

A NEW protective principle for sol

diers has been discovered by an Italian, Signor Benedetti. Experimentation shows that great resistance is offered by substances that have air within their cells. The principle may be illustrated in this manner: fire under precisely the same conditions in both cases, a bullet at each of two calendars, one of which consists of thick sheets of paper, the other of thinner sheets. The ball will penetrate farther into the calendar of heavier material. This difference is due to the elasticity of the layer of air that is imprisoned between the successive sheets. The thinner the cushion of air, the more elastic it is, and the more sharply it reacts.

Benedetti, adopting this principle, has constructed a cuirass of a kind of felt. It is not rough, however, like ordinary felt. The special features of this new device for stopping bullets the inventor has not as yet disclosed in any detail.