54 Galvanic ETpeyiments. 



had a certain dip and variation, and that the angle of varia- 

 tion, the quantity of which I am sorry I cannot recollect, 

 was uniformly the same in all his experiments. It differs 

 however from that of the magnetic needle, and the positive 

 pole always dips. 



IX. Galvanic Experiment'!. By M, Ritter*. 



JL HOUGH I have for some time past employed myself 

 Hjore in the physical than in the chemical part of gal- 

 vanism, I have, however, had occasion to make some ob- 

 servations in the latter departnienl. I have, for example, 

 formed of the oxide of iron an indigo blue extremely beau- 

 tiful. To obtain this oxide you must take a glass tube six 

 inches long, with a diameter of half or three quarters of an 

 inch. You fill the tube a third or fourth part with mer- 

 cury, and the rest with water. Introduce into each end of 

 the tube a thick iron wire ; place the tube in a somewhat 

 inclined position, and make the superior wire communicate 

 with the positive pole, J^nd the inferior wire with the nega- 

 tive pole. After some hours the surface of the mercury 

 will be found covered with a blue oxide of iron. This oxide 

 is produced by the iron of the positive wire, which is par- 

 tially reduced by the negative wire, {t deoxidates itself at 

 tirst into a green oxide, and afterwards into a blue oxide. 



Another inleijesting product which I obtained is the 

 oxide of silver hyperoxidated. This oxide is formed in any 

 solution of silver^, on the side of the positive gold wire of 

 the pile. It has a perfect metallic sound, conducts electri- 

 city and galvanism exceedingly well, is very friable, and 

 has an appearance of galena of iron. It often forms lances 

 or columns, slender and straight, of the length of from 3 to 

 4 inches, and frou) half a line to three-quarters of a line in 

 thickness. These columns represent in their wholclength a 

 succession of unuitcrrupted crystals, in the form of andreo- 

 lite, so that each section across the colunms gives in some 

 sort the shape of a Greek cross, I should have much to 

 add to describe completely this product ; but an experiment, 

 and, if needful, the assistance of the microscope, will afford 

 a much better idea of it than I could give by description. 

 The hvperoxide of silver, reduced to powder, andthrowninto 

 simple muriatic acid, produces, even in cold, a very strong 

 effervescence, acconipanied wiih an abundant discngage- 



* From I'm !/■. /;.,".. Journal, Ho. 17. 



nicnt 



