The daily morning journal and courier., 1906-12-17
THE GAS MANTLE.
uSEFUL ILLUMINANT DISCOV
 BRED BY MERE ACCIDENT.

How Dr. Carl Auer Won Welsbach Made the Discovery--How the Cotton is
 Treated and the Chemicals Used to Perfect the Light Giving Properties.
 What a power is King Cotton. This valuable product of American soil all most caused England to take sides in war.
 The United States produced last year 13, ,556,S41 bales of cotton, the net weight of each bale being four hundred and eighty-six pounds, thus representing a cotton crop of something like 6,56S, ,633,- 726 pounds.
 That cotton is closely allied with the gas industry is explained by the pres enoe of the incandescent gas mantle, which in it's first stage is constructed from cotton. It has probably never oc- cured to you how many persons and operations arc necessary to produce a spool of cotton. OOuh great-grand- mothers could not purchase one. They obtained cotton as it came from the boil, spun it on a wheel and then twisted it into desired form to be bleached if it were to be made into ta- ble napery, or else left unbleached for sheets and pillow cases as were com mon in our grandparents time. The planter has the cotton picked, pressed into bales, shipped to the mill, and there twisted into threads of the de- sired thickness. and then, after being bleached, wound on spools ready to go to the manufacturers of mantles
 Elias Howe patented the sewing ma chine in 1846, It was not a great step thereafter to make a machine tQ take the place of the knitting machine. A machine not unlike that used for mak- ing stockings is used in the knitting of a gas mantle, only, instead of the nee dles being so arranged as to form the foot of the stocking, there is knitted a continuous circular web, such as we have often seen children make with an old cotton spool and four pins stuck in lone end. The web for the gas mantle is knitted in great lengths, and is later cut into such lengths as are needed tc l form the mantles of a desired size IRoughly speaking, the standard man. tie is three and one-half inches long yet it requires nine inches of the web- ping to make mantle of that length The cotton, instead of being a single thread, is woven into a cylindrical web lbing of great length and about three linches in diameter. The cotton has Before the chemist at the mantle fac tory can treat it, the cotton must bt chemically cleaned, so it is placed 1T an alkaline solution of ammonia whicl removes every particle of grease. The cotton is then rinsed in distilled water to remove the ammonia, and then it i' placed in an acid solution to neutralizt Iany ammonia that may remain, ant also to dissolve such small particles o
 iron as had been given up by the earti when the cotton was growing. This accomplished, the cotton is again wei washed in distilled water, and after drying is ready to so into the chemists hand for impregnation, and advanced one stage further toward the compile
 tion of gas mantle.
 It is strange how by almost an acci
 dent new impetus was given to tn, gas industry by the discovery of tho mantle. Dr. Carl Auer Won Welsbacl was seeking a new filament for the electric bulb, which would give more light than the filament made from hair cane or wire, and to this end was ex. lperimenting with certain of the rare earths. In the course of his work, Dr l Von Welsbach noticed that when some of these earths came into contact witt the blue flame burner of his stove, z livery intense light appeared. It ther became a matter of only short time when he was able to discover what chemicals had produced this light These he found to be thorium and ceri Ium combined in proportion of nine ty-nine per cent. of the thorium an( one per cent. of the cerium. If the chem icals were made plastic and moulded they were too thick to be heated suffi Iciently to emit an appreciable light lThen came the clever part of the in vention and by an experiment yot you yy urself may make you may set how it came about.
 Take a little water and add common salt until no more salt can be dissolved Tn this solution soak three or foul Ipieces of cotton thread about twelve inches long, loosely twisted together and knotted at each end. After 8 few moments remove the threads and let them thoroughly dry; then suspend them in a convenient manner and tie a trifing weight, such as a finger ring, tC one end of the threads. You can now burn out all the original cotton, if it is perfectly dry, by applying the flame oi an alcohol lamp or wax taper at the top, and the salt crystals remaining will have sufficient cohesive power tC support the ring. In a manner precise. fly similar to this is the gas mantle made, but substituting the thorium- cerium compound for the table salt anG the woven webbing for the strands of threads. We then perform the process of what is called the tmpregnation of the mantle; that IS, the cotton is i'm. lpregnated with the salts of the rare earths, thorium and cerium. This inn lpregnation having been completed. the lwebbing is thoroughly dried and then