300 Notices respecting New Books. 



appears to be the best means o£ rapid approximation to mean (sec- 

 tional) velocity, but the redaction must (at present) be effected by 

 a coefficient to be found by previous special experiment at each site. 

 Besides these the author enumerates several minor results of in- 

 terest. Enough has been said to show that the work is a highly 

 technical one; but though it is caviare to the general, it appears to 

 be a most carefully compiled account of a series of experiments 

 of great interest in its special department ; and every thing has 

 been done, in the way of tables, plates, and description, to put stu- 

 dents of this particular branch in a position to follow the lines on 

 which the experiments were carried out. 



Experimental Researches into the Properties and Motions of Fluids, 

 with Theoretical Deductions therefrom. By W. Ford Stanley. 

 London : E. and F. N. Spon, 1881, pp. 550+xvi. 

 " I had taken for the amusement of my leisure an experimental 

 examination of the undulatory theory of light, which I could not 

 satisfactorily comprehend. In following up my experiments for 

 two years, I found my eyesight impaired, and was advised that it 

 would be necessary to leave these experiments, and also close 

 application to reading, for some years, which I did Aery reluc- 

 tantly. One branch of experiment, somewhat relative to my 

 former studies, however, appeared open to me. The theory of 

 undulation of light was generally introduced to our conception by 

 philosophers by similitudes of the motions of water-waves and 

 sound-waves ; I thought I would investigate experimentally, as 

 far as possible to me, to be assured our conceptions of these 

 motions were real, upon inductive principles, similar to those I 

 had been employing for investigation of light. In this subject, 

 taking no preconceived theory whatever for my experiments, I 

 soon became absorbed in observations of the motive effects evident 

 in the directions taken by impressed forces in fluids under various 

 conditions of resistance ; wherein it appeared to me quite evident 

 that there was yet an immense amount of Avork to be done in 

 researches in the motions of fluids, before theoretical principles of 

 the sciences of hydrodynamics and acoustics could be fixed upon 

 mechanical principles with any great precision. It was therefore 

 clear to me that in this direction I might, if I had the ability, 

 enter upon fields of research quite as new as in my former 

 studies." 



This quotation will serve a double purpose : it will show that the 

 author's style requires the aid, which he himself states that his 

 book lacked, " of some well-read or well-instructed student " to 

 prune it ; and also how the present work has come into existence, 

 in being the record of a very great number of apparently carefully 

 performed experiments. 



There is an immense deal of matter, accompanied by numerous 

 plates, which may possibly in skilled hands be worked up, in some 

 future treatise on hydrodynamics, into a more elegant form. In the 



