MISCELLANEOUS.

Bush Advocate, Volume XVI, Issue 603, 3 January 1905, Page 6

MISCELLANEOUS.

. THE MAKING OF A WELSBACH MANTLE BRIEFLY TOLD. The incandescent gas mantle was invented by Aver von Welsbach in 1885, and patented all over, the world. The manufacture and use of mantles was first taken up in Austria, and has since found its way in all the civilised, countries where gas is introduced. At the present time it is estimated that no less than one hundred and fifty millions of mantles are manufactured annually. In the United States, although there are about forty millions manufactured annually, the industry is only partly developed. The public is gradually learning to use the mantle. The mantle is made as follows : A cone or spool of Not 40 white cotton thread is knitted into a stocking or. hose, about two inches in diameter. This stocking is thoroughly washed and dried. Then it is saturated with, a solution of nitrate of thorium and one per cent, of nitrate of cerium. The thorium is manufactured from a sand, called monazite, which is found in Brazil and in. the State, of Carolina, and is rather expensive, being sold at 6. dollars 5d cents per pound. .One pound of nitrate of thorium yields from 300 to 350 mantles, depending on the quantity distilled. After the cone has been washed and dried it is either cut to proper size and impregnated with the thorium solution, or is first impregnated and then cut to the required lengths; The impregnated stockings, after being . cut and dried, are sewed at one end with asbestos thread, so as to form a head provided with a loop, which serves to hold the mantle in process of manufacturing and when in use on the burner. ■ . Tnen the impregnated stocking is hung on a wire by the asbestos loop, and heated in a gas flame of the Bunsen type. This is done in order to burn out the thread. ■ The ' next process is called ' the shaping. The mantle now consists only of ashes of thorium (oxide of thorium), and is carefully held over a Bunsen flame, and gradually given the right shape, at the same time being hardened. As soon as the mantle is shaped and hardened it is practically completed; but in order to protect it from breakage it .is dipped in a stiffening solution. . There are many forms of dip, but the one most used is made of ... ■-... . «>«■

soluble cotton (guncotton) dissolved in good alcohol and acetone. To this mixture castor oil and shellac are added. Before the mantle can be used on a burner this dip or coating must be burned off.—Scientific American. _