420 Correspondence of J. Nickles. 
surface and interior. The central parts in all cases contained less tin 
than the surface. For example, in the alloy of 97 of copper and 3 of 
tin, the = i pal in tin for the two parts had the ratio of 1 to 3°97. On 
adding to the alluy 1 p. c. of zine, the homogeneity was much increased, 
the ratio were 1: 1-45. 
Under Louis XIV, the cannon were of better ene than those of 
the present ind zinc was mixed with the metal, e condition of 
brass. The trials made in our time have failed pacath the zinc was 
introduced directly into the alloy while in fusion, in which case the 
zine is burnt off and forms no combination with the fused metal. 
Traité des Poisons, ou Toxicologie appliquée a la Medicine ven 
la Physiologie et a la Whdnaucnttane ar le Docteur Ca. FLaNnpiIN. 
vols. in 8vo. Paris, chez Ma llet-Bachelier.—The fires eoldnip of we 
Poisonous substances are not, as has been said, irritants, etc., but sub- 
stances not capable of being assimilated, which penetrate into the or- 
nism by absorption and become an obstacle to chemical or physio- 
logical action on which life depends. Thos the pathological and thera- 
peutic department of poisoning are distinct. ‘These views characterize 
the work. Il the processes for detecting poisons before and wea 
inhumation are given with details, among which are some that hav 
givena * reputation to M. Fiandin, their discoverer. 
Traité de I Electricité thtociane et appliquée ; par AuG. DE LA RIVE. 
2 vols, in vat Paris. Bailliére—The first voles has just appeared 
self, and that nothing is given 3 witht good authority. 
Mécanique Analytique par LaGRance, 3d edit., revue et apnea’ pat 
Berrranp. 2 vols. Paris, chez Majiet-Bachelier. —Lagrang pub- 
lished the first edition of his work in 1788. In 1811, the sracipled 
and general applications, contained in the first edition, were extende 
and completed. Some obscure points remained, which one of our 
youngest geometricians, Joseph Bertrand, Examiner at the Polyseaue® 
School: has elucidated with skill, profiting by the progress which 
science had made since that period. The edition of 1811 having been 
exhausted, the new edition en been received with much favor by 
eenerione and mechanicia : 
Lecons sur la Theorie i heesitling de Vélasticité des corps soli ides, 
par Lamé; Shae Byvo, ¢ avec planches. Paris, chez Mallet-Bachelier.— 
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addressed to engineers, physicists, goles ts, aed! especialy to pao 
tical men in these arts, who will find in it, rigorous laws on hi 
of elastic forces, and on the oe i fot constructions. 
La régle a caleul expliquée, ou guide du calculate pled a eg de i 
constructing the sliding computing scale, wid of its 
