The One Science
In an able summary in the Times of the contents of Sir Henry Holland’s Essays on Scientific and other Subjects, we find the following suggestive passages:—“The sciences are so interlacing and coalescing that it would seem as if in a year or two we should only have one huge science embracing all; or, at least, what are now regarded as separate sciences should be considerably reduced in number. This is more or less implied in the controversy on the “Correlation of Forces.” The question is,—Are there really “Forces” in nature? Or should we not rather say that there is but one force appearing under different forms? Among these forces may be mentioned light. The undulatory theory of the transmission of light is as old as Huyghens, but its universal acceptance is an incident of our own day; and it is in our own day that radiant heat has been discovered to be subject to those great physical laws which are the basis of the undulatory theory. Here, then, we find in our time, within the last few years, that the three great sciences of optics, of acoustics, and of heat, reduce their principal facts to the same formula. Or again, take this science of optics in another relation. It has within the last few years proved itself to be the most delicate instrument of chemistry. By the aid of a little starch the chemist can detect the millionth part of iodine in solution. Mr. Faraday has found that a strong ruby tint is given to a fluid by a proportion of gold not exceeding the half-millionth part in weight. These are wonderful results of ordinary chemical analysis; but what are they in comparison with the results obtained through the analysis of the spectrum? By means of it chymists have been able to detect in a compound 1-70,000,000th part of a grain of lithium, and the 1-180,000,000th part of a grain of sodium, the metal of common salt. The method of the analysis is very simple. If a little sodium, for instance, be burnt in a flame, and during the process of this burning the rays be made to pass through a prism, then in a certain defined portion of the spectrum beyond there will appear a thin yellow line, so vivid that it will show even when the sodium has been reduced to the 1-180,000,000th part of a grain. By help of the same analysis we pass on to astronomy, and discover the chemistry of the sun, the moon, and the stars. In the photosphere, or luminous atmosphere surrounding the body of the sun, there has in this way been discovered no less than six known metals.
“In these few examples we indicate roughly but sufficiently the intimate connexion of the physical sciences, and the necessity which is imposed on the student in the present day to know all if he would understand one. It has been said that he who has seen but one work of ancient art has seen none, while he who has seen all has seen but one. We may say the same of science. To know one is to know none, and to know all is to know but one.”