June 20, 1902.] 



SCIENCE. 



969 



all been attained within the brief interval of 

 two hundred and fifty years. It would be 

 quite wrong, however, to consider these 

 achievements of geodesy as marvelous from 

 the point of view of science. They are, 

 rather, just such results as persistent sci- 

 entific investigation has always produced, 

 and such as we may safely predict mil be 

 uniformly produced by peraistent scientific 

 investigation in the future. The element 

 of the max'velous comes in only when one 

 talvcs account of the fact that these grand 

 results were attained by a very small num- 

 ber of men, mostly members of academies, 

 struggling, like our own, to maintain an 

 existence, in whose work the general pub- 

 lic took little interest, and whose names, 

 even now, are much less known than the 

 names of the obscure philosophers and the 

 obscene poets of antiquity. 



Geodesy is undoubtedly the most ad- 

 vanced of the sciences in which measure- 

 ment and calculation have attained a high 

 order of certainty. It has made modern 

 commerce possible, and it seems destined 

 to play a still more important role than it 

 has hitherto in the advancement of terres- 

 trial affairs. It has also made modern 

 astronomy possible, for the certainty of its 

 data enables us to measure not only the 

 dimensions of the solar system, but also the 

 approximate dimensions of the visible 

 universe. 



Not less important to the progress of 

 science and to the general advance in 

 human enlightenment are the achievements 

 of the allied science of geology. It cannot 

 boast, as yet, like geodesy, of a high degree 

 of precision in measurement and calcula- 

 tion, for it deals, in general, with phenom- 

 ena which have not yet been reduced to 

 simple laws. But, on the other hand, its 

 subject-matter is more obvious and tangi- 

 ble, and it appeals therefore more forcibly 

 and continuously to the average mind. No 

 science seems comparable with geology in 



the completeness with which its history and 

 its main processes are contained in the 

 subjects and objects of investigation. 

 "VNTioso would read the story of the earth's 

 crust will find it written and illustrated in 

 infinite detail in the rocks themselves. No 

 vivid or perfervid imagination of the his- 

 torian has concealed the facts or misinter- 

 preted their sequence ; they are all recorded 

 with a truthfulness that shames the 

 straightest hmnan testimony and with a 

 permanency which permits comparison and 

 verification in endless repetition. 



Geology illustrates more clearly, perhaps, 

 than any other science the value of meas- 

 urement and calculation when the order 

 only of the quantity sought can be attained. 

 The determination of the fact, for example, 

 that nothing short of a million years is a 

 suitable time unit for measuring the age 

 of the earth, was an achievement whose im- 

 portance can hardly be overestimated; 

 indeed, our race may yet require decades, 

 if not centuries, to appreciate its full sig- 

 nificance, for in spite of the great advances 

 in our times it appears probable that not 

 one in a thousand of the good people with 

 whom we live realizes how profoundly 

 definite acceptance of such a fact must 

 modify thought. 



A criticism which the devotees of the 

 so-called humanistic learning often apply 

 to such matters of fact, and which is still 

 occasionally accepted by men of science, 

 helps us to see the absolute need of count- 

 less recurrences to the evidence so well ex- 

 hibited in the crust of the earth. "Ah!" 

 says the humanist, "I observe that the 

 physicists and the geologists do not agree 

 on the age of the earth. Some say it is 

 ten million years, others that it cannot be 

 more than two hundred million years, and 

 others that it cannot be less than a thou- 

 sand million years. I conclude, therefore, 

 that so long as your doctors disagree in this 

 manner, we may continue to accept the age 



