358 M. Becquerel ow an Electro-magnetic Balance, 



The only experiment detailed by Lassaigne in direct sup- 

 port of his hypothesis is by no means satisfactory, involving 

 as it does the necessity of the solubility of albumen after its 

 coagulation by alcohol in distilled water; still as the experi- 

 ment is interesting and worthy of repetition, I shall, in justice 

 to the talented chemist who performed it, take the liberty of 

 copying the recital of it. 



" ....Le moyen que nous avons, employe pour y parvenir 

 a ete la coagulation du blanc d'oeuf par I'alcool a 28°, et son 

 lavage k plusieurs reprises jusqu'a ce que la dissolution 

 d'argent n'y demon trat plus la presence du chlore. 



" L'albumine ainsi traitee a ete mise avec de I'eau distillee ; 

 une petite quantite s'y est seulement dissoute, car la solution 

 precipitait par I'acide nitrique Tinfusion de noix de galle, et 

 etait troublee par la chaleur. 



" Nous avons place cette solution dans un tube de verre re- 

 courbe en siphon, et nous I'avons soumise a un courant gal- 

 vanique : elle ne s'est nullement troublee; mais apres y avoir 

 ajoute quelques gouttes d'une solution de chlorure de sodium, 

 nous avons observe au pole positif qu'elle est devenue laiteuse, 

 et qu'elle a depose des flocons blancs." {Ann. de Chim,et de 

 Phys. torn. xx. p. 99.) 



From these observations it appears that in the theory of the 

 action of electric currents on albumen I have been antici- 

 pated; which is rather gratifying to me than otherwise, as I 

 trust that the experiments detailed in my last communication 

 are sufficient, if not to prove, at least to render highly pro- 

 bable, the correctness of the hypothesis proposed by M,. Las- 

 saigne in the paper above alluded to. 



I remain, dear Sir, yours truly, 



22, Wilmington Square, April 4, 1837. GoLDING BlRI). 



hlL^l. Description and Use of an Electro-magnetic Balance, and 

 of a Battery with invariable Currents. By M. Becquerel.* 



TIJITHERTO we have possessed only two modes of com- 

 -■--■- paring the relative intensities of electric currents. One 

 consisting in making a magnetic needle oscillate for a given 

 time, at the same distance, from a conducting wire traversed 

 by currents possessing different degrees of energy, and then 

 calculating the intensity of each by means of the formula for 

 the pendulum ; the other requiring the employment of the 

 galvanometer. 



Neither of these methods enables us to refer the intensities 

 of a current to a common measure that may be obtained with 



• From the Comptes Rendus de f Academic Roy ale des Sciences for 1837> 

 No. 2, &C.J being an abstract of a paper read before the Academy, Jan. 9. 



