of great value in cases of diabetes and other disorders in which ordinary cane-sugar has to be avoided in a patient's diet, was discovered in 1879 while an investigation was being carried on in Prof. Ira Remsen's laboratory that seemed as little likely to lead to practical results as any that could well be imagined.

Any practical man would unhesitatingly have condemned the work as being utterly useless, and I may add that some did condemn it. There was no hope, no thought entertained by us that anything practical would come of it. But lo! one day it appeared that one of the substances discovered in the course of the investigation is the sweetest thing on earth; and then it was shown that it can be taken into the system without injury; and finally that it can be manufactured at such a price as to furnish sweetness at a cheaper rate than it is furnished by the sugar cane or the beet. And soon a great demand for it was created, and to-day it is manufactured in surprising quantities and used extensively in all corners of the globe. Prof. Ira Remsen.

Early in the nineteenth century Sir Humphry Davy succeeded in decomposing caustic potash and caustic soda by means of the electric current, and in obtaining from them the metals potassium and sodium. The experiment was made to settle a disputed question in pure chemistry, but it was the starting-point of an immense industry. At the present time, the only process of commercial importance for making sodium is that of electrolysis of caustic soda, all chemical methods of manufacturing the metal being superseded by it. Caustic soda itself, together with chlorine for bleaching purposes, is obtained from common salt by electrolytic methods on a large scale; and its manufacture is an important industry.

In 1833, Faraday obtained the metal magnesium from a compound of the element by means of electrolysis; and now the magnesium ribbon and powder

used for flash-light and other purposes are almost entirely made by the same method. But the most important application of electricity to industrial chemistry is the electrolytic production of that most useful metal, aluminium, which is destined to compete with iron and steel in its importance. Aluminium is now manufactured exclusively by electrolysis of a fused mineral containing it, though a few years ago it was obtained wholly by purely chemical methods. Unlike the examples already mentioned, the actual process of producing aluminium by electrolysis was not derived directly from a scientific laboratory, yet it and all other electrolytic methods would never have come into being but for the discovery by men of science of the chemical effects of the electric current.

Industrial chemistry has, in fact, been revolutionised by the application of electrical methods; and the foundation of the new branch was laid chiefly by the genius and research of Davy and Faraday, being practically based on the laws enunciated by the latter. Metals, such as copper and iron, are obtained in the highest state of purity by electrolysis; in the United States alone, more than twenty million pounds' worth of copper are electrically refined every year. Silver, gold and lead are also refined on a large scale by electrical methods. Electro-plating with gold, silver, nickel and other metals; electrotyping, which is used in every printing works to obtain copies of type and engravers' blocks; the electrolytic reproduction of medals and similar articles, and a hundred other commercial uses have been found for methods which when first discovered were considered to be of interest only to the world of science. It was the remembrance of such facts as these as to the influence of scientific work

upon industrial progress that induced Huxley to remark, so long ago as 1877, in urging the value of technical education :

I weigh my words when I say that if the nation could purchase a potential Watt, or Davy, or Faraday, at the cost of a hundred thousand pounds down, he would be dirt-cheap at the money. It is a mere commonplace and everyday piece of knowledge that what these men did has produced untold millions of wealth, in the narrowest economical sense of the word. Huxley.

CHAPTER X

PRACTICAL PURPOSE

Purpose directs energy, and purpose makes energy. C. H. Parkhurst.

A life without a purpose is a languid, drifting thing. Marcus Aurelius.

Still o'er the earth hastes opportunity

Seeking the hardy soul that seeks for her. J. R. Lowell.
The Time is great

(What times are little? To the sentinel

That hour is regal when he mounts on guard.)

George Eliot. There are two distinct classes of men: first, those who work at enlarging the boundaries of knowledge, and secondly, those who apply that knowledge to useful ends. Prof. R. W. von Bunsen.

SCIENTIFIC investigations carried on with the single motive of acquiring new knowledge often lead, as we have seen, to results of great practical value. Such applications are, however, only incidental, and in the world of science they provide no test of the importance of the work done. The practical man judges scientific research from the point of view of its direct service to humanity, or that of money-making capacity; and he considers that people who devote their lives to studies having neither of these profitable objects in mind are wasting their time and abusing their intellectual faculties,