Prof. E. Wartmann's third Memoir on Induction. 267 



mann*, Hansteenf, Sclnveigger J, Dobereiner§, Miiller||, 

 Kastner^, Fresnel**, Murray ft? Archbishop Rendu J J, the 

 Abbe Zantecleschi§§, Ampere ||||, and of Mr. Hunt^^, who 

 have all asserted that magnets possess a chemical power. They 

 agree, on the contrary, with the results published by Stein- 

 hauser***, Ermantttj DulkJJJ, Wetzlar§§§, Otto-Linne 

 Erdmannllllll, Berzelius^"^^, the Marquis Ridolfi****, and 

 the Chevalier Nobiiifttt. 



• Ann. de Ch. et de Phys., tome xxxviii. p. 201. f Ibid. p. 206, 



I Jahrbuchcr, tome xiv. p. 84. § Ibid. 



II Kastner's Archie, tome vi. p. 448. 

 ir Ibid. 



** Ann. de Ch. et de Phys., tome xv. p. 219. 



ft Phil. Mag. Nov. 1821. His conclusions are opposed to tiiose of 

 Maschmann and Hansteen. 



\l Ann. Ch. et Phys., tome xxxviii. p. 196. 



§§ Blbliotheca Itaiimut, April 1829. The author appears to have aban- 

 doned his first views ; he does not cite his own experiments, and does not 

 even mention the chemical power of magnets in his Trattato del Magne- 

 tismo e delta Elcttricita. Venice, 1845. 



{Ill Becquerel, Traite de VElectricite, tome i. p. 384. It is to be remarked 

 that several special treatises pass wholly in silence this supposed property 

 of magnetic bodies. Such are the Treatises on Electricity, Magnetism, &c. 

 by Dr. Roget, in the Library of Useful Knowledge, the Manual of Electricity 

 and Magnetism in Lardner's Cabinet CyclopEedia, &c. 



^^ Phil. Mag., Jan. 1846. For more details see Researches on the Influ- 

 ence of Magnetism and Voltaic Electricity on Crystallization and other 

 conditions of Matter, in the Memoirs of the Geological Survey of Great 

 Britain, vol. i. London, 1846. Mr. Hunt himself instances a contradiction 

 between the various results he has obtained with iron wires supported by 

 the poles of a magnet and submitted to a chemical action. He finds that 

 in a solution of crystals of sulphate of copper, the copper is reduced in 

 greater abundance around the north pole, whilst in the acidulated water 

 the volume of hydrogen liberated is always more considerable at the south 

 pole. Von Arnim, at the end of the last century, asserted that the north 

 pole of a magnet is oxidized more in water than the south pole. Ritter 

 subsequently maintained the opposite opinion; but notwithstanding his 

 promise, he never publishetl the sequel of his researches, from which we 

 may infer that he discovered his error, and the equal indifference of the two 

 extremities of a magnet. 



•** Steinhauser of Halle employed a very powerful magnetic apparatus. 

 Gilby Aim., tome xiv. p. ] 25. 



ttt Gilb. ./^«M., tomexxvi. p. 139. 



\\X Dulk experimented at Kijnigsberg with a magnet which supported 

 twenty-five pound;. Kastn. Archiv,ton\e vi. p. 457. 



§§§ Schweigg. Jahrh., tomelvi. p. 118. 



mill Erdmann of Leipsig has submitted to a scrupulous examination all 

 the researches made by his pi'edecessors. His work may be cited as a 

 model of patience and accuracy, Schweigg. Jalirb., tome Ivi. p. 24. 



W^ Juhresbcricht, No. x. p. 43. 



'••* Antulogin di Ftrenze, No. xix. 1822. 



Itft Mcmoiic cd hlnimenti, tome i. p. 301. 



