count in its favor.  In the case of incomplete combustion the cylinders are less likely to be clogged with carbon and the escaping gases do not have the offensive odor of the gasoline smoke.  Alcohol does not ignite so easily as gasoline and the fire is more readily put out, for water thrown upon blazing alcohol dilutes it and puts out the flame while gasoline floats on water and the fire is spread by it.  It is possible to increase the inflammability of alcohol by mixing with it some hydrocarbon such as gasoline, benzene or acetylene.  In the Taylor-White process the vapor from low-grade alcohol containing 17 per cent. water is passed over calcium carbide.  This takes out the water and adds acetylene gas, making a suitable mixture for an internal combustion engine.

Alcohol can be made from anything of a starchy, sugary or woody nature, that is, from the main substance of all vegetation.  If we start with wood (cellulose) we convert it first into sugar (glucose) and, of course, we could stop here and use it for food instead of carrying it on into alcohol.  This provides one factor of our food, the carbohydrate, but by growing the yeast plants on glucose and feeding them with nitrates made from the air we can get the protein and fat.  So it is quite possible to live on sawdust, although it would be too expensive a diet for anybody but a millionaire, and he would not enjoy it.  Glucose has been made from formaldehyde and this in turn made from carbon, hydrogen and oxygen, so the synthetic production of food from the elements is not such an absurdity as it was thought when Berthelot suggested it half a century ago.

The first step in the making of alcohol is to change the starch over into sugar.  This transformation is effected in the natural course of sprouting by which the insoluble starch stored up in the seed is converted into the soluble glucose for the sap of the growing plant.  This malting process is that mainly made use of in the production of alcohol from grain.  But there are other ways of effecting the change.  It may be done by heating with acid as we have seen, or according to a method now being developed the final conversion may be accomplished by mold instead of malt.  In applying this method, known as the amylo process, to corn, the meal is mixed with twice its weight of water, acidified with hydrochloric acid and steamed.  The mash is then cooled down somewhat, diluted with sterilized water and innoculated with the mucor filaments.  As the mash molds the starch is gradually changed over to glucose and if this is the product desired the process may be stopped at this point.  But if alcohol is wanted yeast is added to ferment the sugar.  By keeping it alkaline and treating with the proper bacteria a high yield of glycerin can be obtained.