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ted out of tubes through extremely minute holes into acidulated water, each tiny stream becomes instantly solidified into a silky thread which may be spun and woven like that ejected from the spinneret of the silkworm. The origin of natural silk, if we think about it, rather detracts from the pleasure of wearing it, and if "he who needlessly sets foot upon a worm" is to be avoided as a friend we must hope that the advance of the artificial silk industry will be rapid enough to relieve us of the necessity of boiling thousands of baby worms in their cradles whenever we want silk stockings. On a plain rush hurdle a silkworm lay When a proud young princess came that way. The haughty daughter of a lordly king Threw a sidelong glance at the humble thing, Little thinking she walked in pride In the winding sheet where the silkworm died. But so far we have not reached a stage where we can altogether dispense with the services of the silkworm. The viscose threads made by the process look as well as silk, but they are not so strong, especially when wet. Besides the viscose method there are several other methods of getting cellulose into solution so that artificial fibers may be made from it. A strong solution of zinc chloride will serve and this process used to be employed for making the threads to be charred into carbon filaments for incandescent bulbs. Cellulose is also soluble in an ammoniacal solution of copper hydroxide. The liquid thus formed is squirted through a fine nozzle into a precipitating solution of caustic soda and glucose, which brings back the cellulose to its original form. In the chapter on explosives I explained how cellulose treated with nitric acid in the presence of sulfuric acid was nitrated. The cellulose molecule having three hydroxyl (--OH) groups, can take up one, two or three nitrate groups (--ONO_{2}). The higher nitrates are known as guncotton and form the basis of modern dynamite and smokeless powder. The lower nitrates, known as pyroxylin, are less explosive, although still very inflammable. All these nitrates are, like the original cellulose, insoluble in water, but unlike the original cellulose, soluble in a mixture of ether and alcohol. The solution is called collodion and is now in common use to spread a new skin over a wound. The great war might be traced back to Nobel's cut finger. Alfred Nobel was a Swedish chemist--and a pacifist. One day while working in the laborato
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