Page:Popular Science Monthly Volume 70.djvu/263

Rh this country to learn that lamps burning alcohol for light on this principle are to be numbered literally by the hundreds in Germany to-day. At a recent competition in that country for a prize for the best lamp no less than 99 new designs were entered.

These lamps are efficient, the best using only 16 to 20 cubic centimeters of 95 per cent, alcohol for ten hefner candle power hours. They are long lived, and will last without renewal of wick or mantle much longer than the ordinary incandescent electric lamp lasts. Not the least of their advantages in these days of domestic difficulties and problems is their extreme cleanliness.

The questions as to the efficiencies of the denatured alcohol lamps may be summed up by giving the results obtained by Professor Rousseau of Brussels. He has carried out many experiments and concludes that denatured alcohol at 31 cents a gallon furnishes a slightly cheaper light than kerosene at 15 cents a gallon.

But the subject is by no means closed. These alcohol lamps are slow in getting started and a minute or a minute and a half elapses after the match is applied before they are emitting their maximum light. This is because a portion of the alcohol must be vaporized before the heat is great enough to raise the mantle to full incandescence. This little detail is enough to condemn the lamps with many. That their imperfections are fully recognized is demonstrated by the fact that the government of France offers a prize of $10,000 for a device to burn alcohol under exactly the same conditions under which petroleum may be burned for lighting purposes. Similar prizes are also awaiting the fortunate inventor in Germany.

Questions involving the use of denatured alcohol in chemical industries must be omitted here, as anything like an adequate exposition would require much space. They are questions of great magnitude, involving perhaps the establishment of large and important manufactories.

In these as in all the uses of alcohol the presence of any denaturing agent whatever is at best a great nuisance. As was justly said by Professor Erdmann, of Halle, in a discussion of the subject, "It is most illogical and contrary to the most self-evident principles of economy to go to an expense in order to make a useful material less useful." But, as a recent newspaper editorial said, "It is one of the penalties which humanity as a whole must pay for the failings of a minority."

The cost of ethyl alcohol to the manufacturer is a subject upon which divergent opinions are held. It depends upon so many variable factors that it is doubtless different for each manufacturer, and moreover must differ from year to year if not from month to month.