Quite different is it with alcohol, which it seems likely may be the fuel of the future. Some people will be inclined to exclaim "What a pity to burn it!" since to many the word conveys ideas of another sort altogether. There are many nowadays, however, who, like the writer, have none but a scientific interest in it. To such whisky, for example, is but "impure" alcohol, and it is without the "impurities" that it may become of vast use to the world, thereby possibly repaying man for some of the harm which in the past it has inflicted upon him. Alcohol, again, is a hydrocarbon. It is really more correct to speak of it in the plural, as "alcohols," since there is a large group of substances all of the same name. Two of these are of the greatest importance, methyl alcohol and ethyl alcohol. The former is obtained from wood, hence it is sometimes called wood spirit. Wood is strongly heated in an iron still, and the methyl alcohol is given off in the form of vapour, which on being collected and cooled condenses into liquid. It is exceedingly unpleasant to the taste: if it were the only kind there would be no consumption of alcohol as a drink. The second kind mentioned is obtained by the agency of germs or microbes, and the story of its production is so interesting as to demand a little space. We will commence with the maltster. He performs the first part of the operation. Starting with ordinary barley, by the action of heat, aided by natural growth, he produces the raw material on which the brewer may work. Now barley, like all grain, is largely made up of starch, and although starch will not make alcohol, it can be turned into sugar, which will. So the task of the maltster is to commence the change of the starch in the grain into sugar. First of all it is soaked in water and spread upon floors and heated until it begins to sprout. There is a little part in each grain called the endosperm, which is the embryonic plant, and the starch is really the food provided by nature to nourish the growing endosperm until such time as it shall be strong enough to draw its nourishment from the soil. In order that it may not be washed away prematurely, the starch is locked up by nature in closely fastened cells, and, moreover, it is insoluble, so that water cannot carry it away. The endosperm, however, has at its disposal certain substances known as enzymes (and it increases its store of these as it grows), one of which is able to dissolve away the walls of the cells, to unlock the treasures, as it were, while the other turns the insoluble starch into soluble matter, in which state the growing organism is able to make use of it as food.