The temperature attained by the burning gases in the combustion chamber of a gasoline motor cylinder, at the moment of explosion, is in the neighborhood of 3000° Fahr., while the temperature of the exhaust is from 700 to 900°.

A new and simple method for testing eggs is published in German papers. It is based upon the fact that the air chamber in the flat end of the egg increases with age. If the egg is placed in a saturated solution of common salt it will show an increasing inclination to float with the long axis vertical. A scale is attached to the vessel containing the salt solution so that the inclination of the floating egg toward the horizontal can be measured. In this way the age of the egg can be determined almost to a day. A fresh egg lies in a hor-zontal position at the bottom of the vessel; an egg from 4 to 5 days old shows an elevation of the flat end, so that its long axis forms an angle of 20 degrees. With an egg 8 days old the angle increases to 45 degrees; with an egg 14 days old to 60 degrees, and with one 3 weeks old to 65 degrees, while an egg a month old floats vertically upon the pointed end.

Piassava is a fiber made from the bamboo tree and is used in Europe to make brooms, brushes, and the like. In Liberia the bamboo is taken from the tree and placed in water until the outer covering decays. It is then beaten in a forked stick, erected for the purpose, until there remains only the fiber, which is weighed and bound in bundles much like American wheat, except that it is bound at both ends. This is the best method of obtaining the bamboo fiber. The other method, beating the bamboo dry, breaks many of the strands and produces an inferior fiber.

Two well-known Chester, Nova Scotia, men, A. M. Church and Mr. Cleveland, the latter a blacksmith, are satisfied that they have succeeded in hardening copper, and E. B. Church has a piece of metal treated by the process which appears to be very hard. He also has a razor made of their hardened copper, with which one can shave. Having been made in a blacksmith shop the razor is necessarily crude, but the blade is hard and carries a sufficiently sharp edge to remove superfluous hair. The elder Mr. Church writes that by the process the metal can be hardened to any degree.

The amateur mechanic should make all the tools and lathe fittings he can, rather than buy them, as by so doing he gains valuable experience, and when he comes to make an engine, or some other larger machine, he can go at it with confidence that he can build it.

The Westminster Bridge to Tooting tramway will be constructed by the London County Council on the conduit system, at an estimated cost of £251,900. The adoption of the trolley system would have meant a decrease in the capital expenditure corresponding to a reduction of £1,900 in the annual cost of upkeep. The advantage obtained in return for the extra cost has been the absence of any disfigurement of the streets.

The fire risk with incandescent lamps is commonly supposed by the ordinary user to be nil, but " Cassier's Magazine" publishes a reminder that while the view is fairly warranted, it is not altogether accurate. For example, in three months of last year at least five fires were caused by the ignition of inflammable materials due to heat generated by electric incandescent lamps. Systematic tests have been made to determine the heating effects of and the extent of the danger of fire from these lamps when in proximity to inflammable materials, and it was found that a 16-candle-powar incandescent lamp, immersed in 1/2 pint of water, caused the water to boil within an hour. A similar lamp, encased in two thicknesses of muslin, caused it to smoke in three minutes, and in six minutes, when fresh air was admitted to the interior, the muslin burst into flame. A newspaper against which the lamp pressed, ignited in three quarters of an hour, and an article of celluloid ignited in three minutes under the same conditions. There is, however, no comparison between security from fires due to the use of the incandescent lamp and that of oil lamps; the published statistics show that accidents and explosions due to the use of oil lamps number many thousands every year.