Extracts from Berzeliiis's Annual Report for 1843. 191 



that two iodized silver plates, plunged in water in the dark, afford no 

 current of electricity when connected by a galvanic multiplier, — but 

 that a current is immediately produced when the light strikes the iodi- 

 zed side of one of the plates. The plate receiving the influence of the 

 sun becomes positive. 



Nitric Acid.—U. Millon (Ann. der Chim. und Pharm. XLIV, 109) 

 has made a great number of experiments upon the solvent power of 

 nitric acid upon the metals ; and he has discovered that when per- 

 fectly exempt from nitrous acid, it possesses only a very feeble solvent 

 power at the ordinary temperature, even upon metals that we know it 

 dissolves with the greatest energy. This is owing to the fact that the 

 nitric acid ordinarily employed contains nitrous acid, although colorless. 

 If nitric acid is deprived of nitrous acid by ebullition, and then added 

 to a metal which it does not dissolve, it is only necessary to add a very 

 small quantity of some nitrite to bring about the commencement of the 

 solution. M. Millon explains this phenomenon by supposing that the 

 veritable oxidizing agent is nitrous acid, — this acid forming a nitrite 

 with a disengagement of nitric oxide, (part of the acid has been decom- 

 posed to oxidize the metal, and from this nitric oxide is the residue,) 

 which becomes converted into nitrous acid at the expense of the nitric 

 Eicid ; the nitric acid in its turn drives the nitrous acid from the newly 

 formed salt, and in this manner there is constantly a sufficient quantity 

 of nitrous acid, until the whole of the nitric acid becomes saturated or 

 the metal entirely dissolved. 



Tension of Sulphuric Acid. — It has been shown by Baron Wrede 

 and by M. Vogel, that air or gas passed over sulphuric acid to be dried 

 always contains a small portion of this acid. M. Vogel placed under 

 a bell glass some concentrated sulphuric acid, with a plate containing 

 the chloride of barium ; they were left together for five days, and upon 

 dissolving away the chloride, he obtained a residue of sulphate of ba- 

 ryta, weighing I'Oll grains. 



New Sulphur Acid. — MM. Fordos and Gelis (Ann. de Chim. et de 

 Phys. VI, 484) has discovered a new sulphur acid, which has a singu- 

 lar composition. When to two equivalents of hyposulphite of soda, 

 (Na S,) one equivalent of iodine is added ; the iodine dissolves and af- 

 fords a limpid and neutral solution, containing 1 at. iodide sodium and 

 1 at. of a salt formed of 1 at. of soda, 4 ats. of sulphur, and 5 als. of 

 oxygen. The two atoms of hyposulphurous acid combine, in this re- 

 action, with the oxygen liberated by the iodine, forming an acid com- 

 posed of 4 ats. sulphur and 5 ats. oxygen. They have called this acid 

 hyposulphuric bisulphuretted. 



Soluhility of Chlorine in Water. — M. Pelouze (L'Institut, No. 473, 

 11) determined the quantity of chlorine dissolved by Gay-Lussac's 



