Notices respecting New Boohs. 



349 



Observations. 



Experimenter. 



K . 



K. 





Lenz. 



10 3 x 82-36 







Matthiessen. 



10 3 x 131-50 







Matthiessen. 



10 3 x 125-70 



+0-00418 





F. Weber. 



10 3 x 119-33 







L. Lorenz. 



10 3 x 107-64 



+0-00475 



Bi cooled slowly. 



Leduc. 





+0-00455 



Bismuth plate. 



Leduc. 





-0-00127 





h ighi. 



10 3 x 108-49 





Bismuth plate. 



Von Ettingsh. & Nernst. 



10 3 x 208-33 



-0-0012 





C. L. Weber. 





-0-0006 





Lenard & Howard. 





+0-0052 



Bi cooled slowly. 



Edw. van Aubel. 



10 3 x 107-99 



+0-00429 



Bi hai-dened. 



Edw. van Aubel. 



10 3 x 108-69 



+0-00422 



I have great pleasure in expressing my thanks to Profs. 

 Wiillner and Classen for having so kindly furnished me with 

 the valuable materials necessary for my researches. 



Physical Laboratory of the Polytechnic School, 

 Aix-la-Chapelle. 



XLI. Notices respecting New Books. 



Force and Energy. A Theory of Dynamics. By Gbant Allen. 

 (Longmans, Green, and Co.: 1888. Pp. xiv + 161.) 

 ^HOSE familiar with Mr. Grant Allen's more popular writings, 

 -*- whether in Natural History or Fiction, were hardly prepared 

 for his appearance as the Author of a new theory of Dynamics, a 

 branch of Science supposed to be among those the bases of which 

 are most firmly established, and verified by thousands of instances 

 of the accordance with its predictions of phenomena such as the 

 recent " Occuitation of Jupiter by the Moon, the disappearance 

 taking place at 7 h. 4 m. August 7th, afternoon, at 25° from the 

 vertex . . ." 



In a prefatory " Apology " Mr. Allen explains that the present 

 book is the development of " a little twenty-page pamphlet, bearing 

 the same title, printed privately at Oxford in 1875 for presentation 

 to a few physical specialists." The result of the earlier appeal, we 

 are told, was that " some said his theor} r was only what was already 

 known and universally acknowledged; while others of them said it 

 was diametrically opposed to what was already known" — a result 

 not unlikely to happen, according as the specialist in dipping into 

 the brochure chanced to alight on one or another passage. 



The " summum genus " of Mr. Allen's theory of dynamical 

 science is " Power," of which " Force " and " Energy " are " sorts," 

 the former "initiating or accelerating aggregative motion, while it 

 resists or retards separative motion;" the latter "resisting or re- 

 tarding aggregative, while it initiates or accelerates separative 

 motion." " Gravitation, Cohesion, Capillarity, and Chemical 

 Affinity are Forces; Heat, Electricity, and Light are Energies." 

 Phil Mag. S. 5. Vol. 28. No. 173. Oct. 1889. 2 C 



