Miscellanies. 383 



composed by oxide of copper, it gives no trace of hydrogen gas. Its 

 composition by the analysis of Serullas, is three atoms chlorine, one 

 atom phosphorus and one atom sulphur. — Idem. 



25. Atomic weight of iodine and bromine.— M. Berzelius has de- 

 termined that the atomic weight of iodine is 789.145, and the density 

 of its vapor 8.7011. The atomic weight of bromine seems to be 

 about 489.15, and the density of its vapor 5.3933.— An. de Chim. 

 Idem. 



26. Economic Lighting.— At the Tulloch Bleachfield, a young 

 man, named A. Reed, has constructed an apparatus, by means of which 

 he is enabled to procure from the wood, which they are in the prac- 

 tice of burning, in order to obtain acetic acid, gas sufficient to light 

 the whole premises. By this ingenious device a most important sav- 

 ing is effected, since no more wood is necessary for both the gas and 

 the acid, than was formerly used for the acid alone.— Lond. Median. 

 Mag. Jan. 2, 1830. 



27. Decomposition of Water.— In order to determine the power of 

 a small galvanic battery of twelve pairs of four-inch plates, on Dr. 

 Wollaston's plan, L. Richard states, that he brought the wires from 

 the two poles into contact with the platina wires of two glass tubes, 

 three-eighths of an inch in diameter, and three inches long, filled with 

 water, and placed in a glass containing the same fluid. Exceedingly 

 minute bubbles of gas rose in the tubes, but it would have required ma- 

 ny hours to procure a quantity sufficient for determining its proper- 

 ties, when by accident a small quantity of dilute nitric acid was pour- 

 ed into the glass containing the tubes. Immediately great quantities 

 of gas arose in both the tubes, and again, when a small quantity of 

 pure nitric acid was poured into the glass, the power of the battery 

 was so considerably augmented, that the tube in connection with the 

 negative pole, was filled with gas in a few minutes. The gases prov- 

 ed to be oxygen and hydrogen in proper proportions, whence it was 

 inferred that the nitric acid somehow increased the power of the bat- 

 tery, without being itself decomposed.— Idem. 



Homogeneous and Hetero 



A letter from 



Berzelius to M. Dulong, was read to the French Academy on the 9th 

 of August, in which he states that his analysis of tartaric acid differing 

 from that of Proust, in which he had great confidence he repeated it 

 and obtained the same result as Proust. But, after having analyzed 



