THE MAKING OF A WELSBACH MANTLE BRIEFLY TOLD.

Waimate Daily Advertiser, Volume VI, Issue 11, 28 January 1905, Page 1 (Supplement)

THE MAKING OF A WELSBACH MANTLE BRIEFLY TOLD.

The incandescent gas mantle was invented by Auer von Welsbach in 1885, and patented all over Che 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 fit njantles are manufactured annually. In the United States, although there arc about forty million* 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 No. 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 ia found in Brazil and in the State of Carolina, and is rather expensive, being sold at 6 dollars 50 “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 cither cut to • proper size and impregnated with the thorium solution, or is first impregnated aud tncn 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 server to hold' the mantle in process of manufacturing and when in use on the burner.

Then the impregnated stocking is hung on a wire by the asbestos loop, and heated

in a gas flame of the Bunsen type. Thia

is done in order to burn out the thread. The next process is called the shaping. The mantle now consistb only of ashes of thorium (oxide of thorium), and is carefully held over a Bunsen lame, and giadually 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 arc added. Before the mantle caff be used on a burner this dip or coating must be burned off.—Scientific American.