Page:Popular Science Monthly Volume 73.djvu/111

Rh To the geologist, yonder snow-capped peaks symbolized eternity; to the physicist, the mountains were as transient as the clouds.

A calm statement of the geologists' attitude was made before the British Association in 1892 by Sir Archibald Geikie. In one place he expresses himself as follows:

Lord Kelvin is willing, I believe, to grant us some twenty millions of years, but Professor Tait would have us content with less than ten millions. . . . I frankly confess that the demands of the early geologists for an unlimited series of ages were extravagant. . . and that the physicist did good service in reducing them. . . . That there must be some flaw in the physical argument I can, for my own part, hardly doubt, though I do not pretend to be able to say where it is to be found. Some assumption, it seems to me, has been made, or some consideration has been left out of sight, which will eventually be seen to vitiate the conclusions, and which when duly taken into account will allow time enough for any reasonable interpretation of the geological record.

Five years later an American geologist, Professor T. C. Chamberlin, invaded the domain of physics and made a vigorous attack on Lord Kelvin's argument, challenging the correctness of some of his assumptions. This criticism did not secure the attention it deserved, for scientific events soon took a different turn.

Lord Kelvin's address of 1897 is permeated, as Professor Chamberlin puts it, "with an air of retrospective triumph and a tone of prophetic assurance." "It is only by sheer force of reason," says Kelvin, "that geologists have been compelled to think otherwise, and to see that there was a definite beginning and to look forward to a definite end of this world as an abode fitted for life." Nor was this feeling of retrospective triumph confined to Lord Kelvin or to the students of the problem of the age of the sun and earth. At the close of the century physicists and chemists gloried in the triumphs of their predecessors, in such achievements as are indicated by the words "conservation of energy," "conservation of mass," and "atomic theory." In physical research the nineteenth century was a golden age. It produced Faraday, Helmholtz, Mayer, Joule, Kelvin, Rayleigh, Rowland and many other great men. With the close of the century timid souls doubtless feared that the golden age had come to a close, and they perhaps experienced strange emotions like those attributed to Adam in the Garden of Eden, on seeing the sun go down, not knowing that it would ever rise again.

Others were perhaps haunted by another fear—a feeling that the great and fundamental truths of science were all revealed to the full sight of man, and it now remained only to work out the less important