Page:Popular Science Monthly Volume 91.djvu/432

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��Popular Science Monthly


��Maqnesium Tape

���The current then uses the path of vaporous carbon as a conducting medium and heats it to a great temperature. The greater the current intensity used, the greater will be the resulting heat produced.

Making Diamonds at Home

The furnace with which Moissan user of the electric arc, conducted startling ex- periments and made many discoveries, is most simple. It con- sists principally of an arc drawn between two large carbon electrodes and supplied with a very heavy current. The arc is enclosed in the cavity formed by two large limestone blocks. In this simple furnace Moissan produced a temperature of sixty-three hundred degrees Fahrenheit and, had it not been for the fact that carbon boils at this temperature, we can not predict how much further the temperature could have been carried.

With the aid of his electric furnace Moissan made as many as one hundred and fifty valuable contributions to science. Among his more notable discoveries was the production of the carbides of nearly every metallic element and the artificial creation of the diamond which is crystallized carbon.

The science of electrothermics has de- veloped many new industries and sub- stances, not only through the efforts of Professor Moissan, but many other inves- tigators as well. Nor have all the industries founded made use of the arc in their furnaces. Many, such as Acheson's for the production of carborundum and graphite, are of a differ- ent type. In Acheson's fur- nace the sub- stances to be converted form a part of an electrical circuit

��Graphite Crucible

��The essential elements which are used in preparing thermit for the laboratory

��and offer such resistance that temperatures as high as sixty-three hundred degrees Fahrenheit have been produced.

It was by means of the electric furnace that Hall made aluminum a commercial article. Before his time it was a laboratory curiosity. Taylor produced carbon-disul- phide and Willson developed a means of producing calcium carbide on a commercial scale. Sodium Peroxide The highest temper- ature ever reached by man was produced a few years ago by two English experimenters, Sir Andrew Noble and Sir F. Abel. This was done by an explosive called cordite, which is a form of smokeless powder composed chiefly of guncotton, nitro- glycerine and mineral jelly. When this was exploded in a durable steel cylinder, a temperature of ninety-four hundred degrees Fahrenheit was produced. This was due to the suddenness of the reaction, and, although of momentary duration, it was an interest- ing scientific achievement nevertheless. With the aid of cordite, Sir William Crookes was able to make small diamonds.

���Using the intense heat of the electric arc in welding street-car rails. Note the head gear worn by the man

��Doff Your Hat to the Goat— Its Milk Saves Babies' Lives

CHEMICAL studies made recently at the Agricultural Experiment Station at Geneva, N. Y., to ascertain the value of goats' milk as a substitute for cows' milk showed marked differences between the two kinds of milk but could reveal no reason why "Goats' milk agrees bet- ter with babies than does cows' milk," the fact that it does so being unques- tioned. The Station main- tains a herd of goats in order that the inves- tigations may be carried out under the best conditions.

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