70 Notices respecting New Books. 



density of caloric, temperature, cohesion, and attraction of finite 

 masses, •which result from these investigations, we must refer to the 

 memoir itself. 



We shall notice, in the last place, Mr. Holditch's memoir " On 

 Rolling Curves." The object of this paper is to determine curves 

 of such a form that, revolving about two centres, one of them may 

 communicate motion to the other, as in the case of the teeth of 

 vi^heels ; with the condition that the curves, in this communication 

 of motion, are to roll upon each other without friction. Euler in 

 the Acta Petropolitana had deduced the characteristic property of 

 these curves, but he did not follow out the investigation so as to 

 furnish actual forms of curves ; nor has the method of obtaining 

 such curves been pointed out by any previous writer. They are 

 commonly found by a tentative process ; but Mr. Holditch thought 

 it worth while to search for rules and forms for their construction ; 

 and these he has found and given the present memoir. Some of the 

 results are very curious and novel. 



Principles of General and Comparative Physiology, intended as an In- 

 troduction to the Study of Human Physiology, and as a Guide to 

 the Philosophical pursuit of Natural History. By William B. 

 Carpenter, M.R.C.S., late President of the Royal Medical and 

 Royal Physical Societies of Edinburgh, &;c. &;c. With 240 Figures 

 on CojDper and Wood. London, 1839. 8vo, pp. 480. 

 The science of physiology has been too generally considered by 

 physical philosophers as beyond their pale. The nature of the 

 phsenomena which it embraces, and the mode in which it is to be 

 pursued, have been regarded as sufficiently distinct to limit the cul- 

 tivation of it, with few exceptions, to those who make it a part of 

 their regular professional studies. We cannot but think that such 

 a state of things may be advantageously modified. Men of general 

 science are constantly invoking the aid of the physiologist, for the 

 determination of most important and intricate questions ; and too 

 often is it found that this aid is unattainable, in consequence of the 

 exclusive notions of the latter, who, from his want of truly philoso- 

 phical principles, cannot meet the difficulties which he is expected 

 to solve ; and, on the other side, physiologists are too often con- 

 tent with a smattering of knowledge on physics and chemistry, 

 which is more likely to lead them wrong than right. We do not 

 mean to assert that there are not many bright exceptions on both 

 sides ; but we maintain that the cause of philosophy would be 

 benefited if the barrier which is supposed to exist between the sci- 

 ence of vitality and that of general physics were broken down, and 

 if the cultivators of each were to make themselves acquainted with 

 the principles of the other, and with the best mode of pursuing and 

 extending both. 



Such appears to have been the object of the author of the volume 

 before us. From the dedication of it to Sir J. Herschel, we infer 

 that he has been trained in the school of physical science ; and 

 throughout the work we perceive the influence of those grand prin- 



