des Agens Physiques sur la Vie, 313 



voted to the applications of all his positions and results, to 

 which we must refer the reader ; for our analysis has already 

 drawn us into a more lengthened detail than we at first con- 

 templated. 



In taking leave of this book, we can only, in conclusion, 

 allude to the appendix upon electricity, which the author thus 

 announces in his introduction. *' En commenyant ces recher- 

 ches, je me suis bientot convaincu que les connaissances phy- 

 siques relatives a l'(5lectricite, n'etaient pas assez avancees pour 

 me fournir les moyens d'ctudier son influence sous les mOmes 

 points de vue sous lesquels j'avais envisage les autres agens. 

 La decouverte recente de M. CErsted, qui lie les ph^nomcnes 

 de I'electricite et du magn^tisme, celles de M. Ampere et 

 de plusieurs autres physiciens, forment une nouvelle epoque 

 dans la science. Les principes qu'ils ont etablis, les inst ru- 

 mens qu'ils ont inventes pour la mesure d'actions inconnues 

 avant, ont fourni a MM. Prevost et Dumas les moyens de 

 faire des recherches tres-int6ressantes sur les rapports de 

 r^lectricit6 et de I't^conomie animale. Je dois a leur amitie 

 un exposd succinct de nos connaissances relatives a ce sujet, 

 qui forme un appendix ti cet ouvrage." 



The subject is unquestionably one of high interest and im- 

 portance, and the attempt to unite different animal functions, 

 such as the production of heat, muscular contraction, secre- 

 tion, nervous action, &c. under one law, referrible to electri- 

 city, though not at present perfected, is fully worthy of the 

 attention of physiologists. 



On Saline Manures. By C. W. Johnson, Esq. 



[Communicated by the Author.] 



It may not, at the present period, when it is a generally enter- 

 tained idea that much of the poorest cultivated land in the king- 

 dom will, from the comparative expense of its cultivation, be of 

 necessity abandoned by the farmer ; it will not be, perhaps, an 

 useless uudertaking to direct the agriculturist's attention to the 

 resources which he possesses in saline manures ; by such term, 

 principally including common salt, chalk, gypsum, and bone- 

 dust. 



The true definition of the word manure must be much more 

 general in its application than some farmers would suppose ; 

 for a cultivator of the rich alluvial valleys of the West of Eng- 



