358 Magnetic Effects of Dr. Harems Calorimotor. 



adhered to the wire as in the preceding experiment. The 

 instrument being then raised from the diluted acid, the fil- 

 ings fell from the wire. These experiments were repeated, 

 and varied by employing different metals to comp/ete the 

 communication between the two galvanic poles. Wires 

 of iron, copper, brass, lead, zinc, silver, and platina were 

 used ; the length of the wire employed being in all cases so 

 regulated, that although it became hot, it was not ignited. In 

 every instance the same magnetic properties were exhibited 

 by the connecting wire ; the iron filings being strongly attract- 

 ed by it, so long as the calorimotor was immersed in the 

 acid solution, and immediately falling from it when the in- 

 strument was raised from the fluid. 



In Vol. VI. p. 83 of the work above quoted, are detailed 

 some experiments of Prof. Moll, in which he succeeded in 

 imparting magnetism to steel needles by inclosing them in a 

 glass tube, about which was wound a spiral of brass wire, 

 and passing strong electrical discharges through the spiral. 

 These experiments were repeated in the following manner: 

 Around a glass tube one quarter of an inch in diameter and 

 four inches in length, was wound spirally, a brass wire, from 

 left to right, forming ten spirals. The ends of the wires 

 were then connected with the opposite galvanic poles and a 

 needle, which had been previously ascertained to be free 

 from magnetism was placed within the tube. The instru- 

 ment was then immersed and remained in the fluid for thir- 

 ty seconds. Upon examining the needle after the plates 

 had been raised from the acid solution, it was found to have 

 become powerfully magnetic, having a north and south 

 pole ; one of which was attracted and the other repelled by 

 the poles of a magnetic needle suspended in the usual man- 

 ner — they also took up iron filings abundantly. The end 

 of the needle which had been placed nearest to the copper 

 or negative side of the calorimotor had acquired north po- 

 larity, while that which had been next to the zinc or posi- 

 tive side had acquired south polarity. This experiment 

 Was often repeated, and always with the same results; the 

 end of the needle placed nearest to the copper plates con- 

 stantly acquiring a north polarity. 



One of the needles which had been magnetized in this 

 manner, was again enclosed within the glass tube, its north 

 pole being placed next to the copper side of the apparatus. 

 The plates were immersed, and again raised from the fluid. 



