1835.] the Advancement of Science. 225 



is found that a marked peculiarity arises. For the far greater por- 

 tion of the report contains the result of Mr Rogers' own reasonings 

 on data, many of which appear for the first time in his essay. It has 

 therefore, more the character of a memoir than of an ordinary re- 

 port. Were any one to adopt this plan in treating of the state of 

 European geology he might be blamed, because the value of such a 

 report would consist in the discussion of a vast mass of published 

 data, and in the comparison of theoretical notions proposed by per- 

 sons of high reputation. But in treating of America this was not the 

 case ; because, first, little authentic was known in Europe on the 

 subject — second, there are few American authors of high repute in 

 geology. This character of originality is certainly well supported by 

 the author's own researches, and it is not surprising if his work 

 contains some errors, still less remarkable that it should have excited 

 some opposition at home. But the writer of the report has really 

 taken much pains, has exhibited much patience, and has brought to 

 his task a competent knowledge of European geology. It has cer- 

 tainly cleared our notions of the general features of American geo- 

 logy, and particularly augmented our positive knowledge of the more 

 recent deposits, as regards organic remains, mineral characters, and 

 geographical features. It is to be continued. 



Another report which is almost entitled to be called a report on 

 foreign science, is that of the Rev. Mr. Challis on the theory of 

 capillary attraction, which is a sequel to that presented at Cambridge 

 on the common theory of fluids, and which the author proposes to 

 follow up hereafter by another report on the propagation of motion 

 as affected by the development of heat. Mr. Challis remarks, that 

 while many questions in physics are to be resolved by unfolding through 

 deductive reasoning the consequences of facts actually observed, there 

 is also another class of questions in physical science, in which the 

 facts that are to be reasoned from are not phenomena ; for example 

 the fact of universal gravitation for which the evidence is inductive 

 indeed, but yet essentially mathematical, the fact not coming itself 

 under the cognizance of any of our senses, although its mathematical 

 consequences are abundantly attested by observations. Mr. Challis 

 goes on to say — " The great problem of universal gravitation which 

 is the only one of this class that can be looked upon as satisfactorily 

 solved, relates to the large masses of the universe, to the dependence of 

 their forms on their own gravitation and the motions resulting from 

 their actions on one another. The progress of science seems to tend 

 towards the solution of another of a more comprehensive nature, 

 regarding the elementary constitution of bodies and the forces by 

 which their constituent elements are arranged and held together — 

 Various departments of science appear to be connected together by 

 the relation they have to this problem. The theories of light, heat, 

 electricity, chemistry, mineralogy, crystallography, all bear upon 

 it. A review therefore of the solutions that have been proposed of 

 all such questions as cannot be handled without some hypothesis 

 respecting the physical condition of the constituent elements of bodies, 

 would probably conduce by a comparison of the hypotheses, towards 

 reaching that generalization to which the known connexion of the 

 sciences seems to point." The author finally remarks, that " Ques- 



VOL. II. Q 



