408 Intelligence and Miscellaneous Articles. 



larity ; only one required the application of a finer needle. They had 

 all therefore, by being turned, obtained permanent magnetism, even 

 those which were of soft iron, and which can neither be permanently 

 magnetized by touch nor by the voltaic current. One of the turnings, 

 7 feet in length, when broken formed two complete magnets. When 

 a turning of puddle steel was broken it exhibited two poles at the 

 fracture, but not so strong by magnetic as the original ones. Even 

 a piece half an inch in length had two poles. 



No connexion could be perceived between the direction of the 

 winding and the occurrence of the poles, analogous to what prevails 

 in magnets on Ampere's theory. In one north pole the windings 

 were in the direction in which the hand of a watch moves, in another 

 In the opposite direction. I found, however, that the turnings had 

 all a sharp edge on one side, but somewhat jagged on the other. 

 The sharp edge is obviously formed where the chisel attacks the 

 metal, so that it can be easily determined where the winding begins 

 and where it ceases. Taking this into account, I found that in all 

 cases a south pole was formed where the turning began, and a north 

 pole where it ceased. 



In five or six of the pieces the magnetism was stronger than in 

 others. This phenomenon did not originate in the length of the 

 turning nor in their nature, that is, whether of cast steel, puddle 

 steel, or soft iron. But I observed that all turnings whose spires, 

 looked at from the south pole, were in the opposite direction to the 

 motion of the hands of a watch, had a stronger magnetism than those 

 whose spires, looked at from the south pole, coincided in direction 

 with the motion of the hands of a watch.— -PoggendorfF's Annalen, 

 September 1864. 



ON THE ALTERATION OE ELECTROMOTIVE FORCE BY HEAT. 

 BY F. LINDIG. 



The following summary is given by the author of the results of an 

 investigation on this subject. 



1. Some of the electrical tensions are dependent on the tempera- 

 ture of the exciters, and change more or less with them. Thus, for 

 instance, copper in sulphate of copper, amalgamated zinc in sulphate 

 of zinc and chloride of zinc, and unamalgamated zinc in solution of 

 chloride of sodium, show an increase of force when warmed ; while 

 with the ordinary measuring-instruments this cannot be with cer- 

 tainty shown in the case of sulphuric acid and solution of common salt. 



2. The change of force is not always in the same direction : thus, 

 while it decreases with the temperature in the case of copper in sul- 

 phate of copper, and amalgamated zinc in chloride of zinc and in 

 sulphate of zinc, with unamalgamated zinc it increases in solution 

 of common salt. 



3. The change is not in all cases proportional to the change of 

 temperature between the temperatures -|-2 and §5°, as is distinctly 

 seen in the case of zinc in sulphate and chloride of zinc. 



4. In accordance with (1) and (2), a Daniell's element is not con- 

 stant with changing temperature when zinc is surrounded with 

 dilute sulphuric acid or solution of common salt. — PoggendorfF's 

 Annalen, September 1864. 



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