262 Translations and abstracts from the French. 



3. Influence of Magnetism. 



(a) On chemical action in general. — The Abbe Rendu., 

 professor of chemistry at Chaniberry, communicated to M. 

 Biot the following experiment. 



A tube bent in the form of the letter V was filled with the 

 tincture of red cabbage. An iron wire was plunged in each 

 branch, and one of them was supported by the north pole and 

 the other by the south pole of a horse shoe magnet. In a quar- 

 ter of an hour the color of the tincture became of a beauti- 

 ful green. It was the same in both branches of the tube. 



The same change was effected, though in much longer 

 time, (two days,) when the wires in two small tubes closed 

 at the extremities, which were plunged in the liquid. 



The discoloration was not the effect of a spontaneous 

 change, for the fluid, of itself, becomes red and not green. 



[t was found, by Ritter, that a magnetized iron wire, com- 

 bined with another not magnetized, produced a galvanic 

 palpitation in frogs. Ritter placed a magnetized iron wire 

 on pieces of glass, in an earthen plate, and poured over it 

 weak nitric acid : the north pole was more rapidly attacked 

 than the south pole, and was much sooner surrounded with a 

 deposition of oxide. 



When three small flasks were filled with water, either pure 

 or slightly acidified, and in the first, the north pole of a 

 magnetized wire was placed, in the second, a wire not mag- 

 netized, and in the third, the south pole of a magnetized 

 Avire ; the oxidation began with the south pole, and was 

 considerably advanced in that, and sensibly with the non 

 magnetized wire, before it was perceived in that with the 

 north pole. In this experiment it was necessary to cover the 

 water with fresh oil of almonds, to prevent oxidation from 

 the air, and to avoid all difference of exposure to solar lights. 

 — Annates de Chim. et de Phys. Juin, 1828. 



(b) Efect of terrestrial magnetism on the precipitation of 

 silver. — -A singular result with respect to terrestrial magnet- 

 ism was obtained in 1817, by Prof Muschman of the Univer- 

 sity of Christiana, and has since been confirmed, by Prof. 

 Hansteen. A tube of the form of the letter V, about half 

 an inch wide and four or five inches long — each branch 

 has a quantity of clean Mercury poured into it, but not suffi- 

 cient to close the communication between the two branches. 



