Miscellanies. 383 



composed by oxide of coppei-, 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 Aveight of iodine is 789.145, and the density 

 of its vapor 8.7011. The atomic Aveight 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 Avood, 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 Avood is necessary for both the gas and 

 the acid, than Avas formerly used for the acid alone. — Lond. Mechan. 

 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 Avires from 

 the tAvo poles into contact with the platina Avires of tAvo glass tubes, 

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

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

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

 ny hours to procure a quantity suflicient 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 poAver of the battery 

 Avas so considerably augmented, that the tube in connection Avith the 

 negative pole, AA''as filled Avith gas in a few minutes. The gases prov- 

 ed to be oxygen and hydrogen in proper proportions, AA^hence it Avas 

 inferred that the nitric acid somehoAV increased the poAver of the bat- 

 tery, Avithout being itself decomposed, — Idem. 



28. Homogeneous and Heteromorphous Compounds. — A letter from 

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

 of August, in v/hich he states that his analysis of tartaric acid differing 

 from that of Proust, in AA'hich he had great confidence, he repeated it, 

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



