THE MATHEMATICAL THEORIES OF THE EARTH. 199 



au(l which always threatens to dampen the anlor of research imme- 

 diately after the attainment of any marked snccess or advance. I refer 

 to the impression of contentment with and acquiescence in the results 

 of science, which seems to find easy access to trained as well as un- 

 trained minds before an inv^estigatiou is half completed or even fairly 

 l>egun. That some such tacit persuasion of the completeness of the 

 knowledge of the earth has at times pervaded scientific thought, there 

 can be no doubt. This was notably the case during the period which 

 followed the remarkable epoch of Laplace. The profound impression 

 of the sufficiency of the brilliant discoveries and advances of that epoch 

 is aptly described by Carlyle in the half humorous, lialf sarcastic lan- 

 guage of Sartor Resartus. "Our theory of gravitation," he says, "is 

 as good as perfect: Lagrange, it is well known, has proved that the 

 planetary system, on this scheme, will endure forever; Laplace, still 

 more cunningly, even guesses that it could not have been made on any 

 other scheme. Whereby, at least, our nautical logbooks can be better 

 kept; and water transport of all kinds has grown more commodious. 

 Of geology and geognosy we know enough; what with the labors of 

 our Werners and Huttons, what with the ardent genius of their disci- 

 ples, it has come about that now, to many a royal society, the creation 

 of a world is little more mysterious than the cooking of a dumpling; 

 concerning which last, indeed, there hav^e been minds to whom the 

 question — Roic the apples icere got in — presented difficulties." This was 

 written nearly sixty years ago, about the time the sage of Ecclefechan 

 abandoned his mathematics and astronomy for literature to become the 

 seer of Chelsea; but the force of its irony is still applicable, for we 

 have yet to learn, essentially, '■'Hoic the apples icere got in^^ and what 

 kind they are. 



As to the future, we can only guess, less or more vaguely, from our 

 experience in the past and from our knowledge of present needs. 

 Though the dawn of that future is certainly not heralded by rosy tints 

 of overconfidence amongst those acquainted with the difficulties to be 

 overcome, the prospect, on the wholes, has never been more promising. 

 The converging lights of many lines of investigation are now brought 

 to bear on the problems presented by our planet. There is ample 

 reason to suppose that our day will witness a fair average of those 

 happy accidents in science which lead to the discovery of new princi- 

 ples and new methods. We have much to expect from the elaborate 

 machinery and i»erfected methods of the older and more exact sciences 

 of measuring and weighing — astronomy, geodesy, physics, and chem- 

 istry. We have more to expect, perhaps, from geology and meteorology, 

 with their vast accumulation of facts not yet fully correlated. Much, 

 also, may be anticipated from that new astronomy which looks for the 

 secrets of the earth's origin and history in nebulous masses or in swarms 

 of meteorites. We have the encouraging stimulus of a very general 

 and rapidly growing popular concern in the objects of our inquiries, 



