Magnetic Effects of Dr. Harems CaJorimotor. 359 



Upon removing the needle, its poles were found to have 

 been unaffectedj the end which had been nearest the cop- 

 per, still retaining its north polarity. The same needle was 

 again submitted to the galvanic action, its north pole being 

 now placed nearest to the zinc plates of the instrument ; 

 upon examination, its poles were found to be reversed; its 

 south pole which had been placed nearest the copper plates, 

 had acquired north polarity, w^iile its north pole which was 

 next to the zinc plates had acquired south polarity* 



A common magnetic needle was then enclosed in the tube, its 

 south pole being placed next to the copperside of the appara- 

 tus. The plates having been immersed the usual time, the 

 needle w^as examined. The end w^hich had previously been 

 Its south pole, and which was placed next the copper plates^ 

 had now acquired north polarity, and in every instance that 

 end of a needle which w^as connected with the negative 

 side of the calorimotor became its north pole, so long as 

 the spiral brass wire upon the glass tube was wound from 

 left to right. 1 then took the same glass tube and wound 

 a brass wire spirally around it, the spirals however, being 

 now wound from right to left. A needle was placed within 

 the tube, and the ends of the spirals connected with the 

 opposite poles of the calorimotor. After the immersion of 

 the plates, the needle was removed from the glass tube and 



S 



was found to have become magnetic — it^ north pole bein^ 

 that end of the needle which had been connected with zinc 

 plates of the instrument, and vice versa. The needle was 

 then again enclosed in the tube and the plates immersed; 

 its acquired south pole being placed in connection with the 

 Zinc plates. When examined, its poles were found to be 

 reversed ; its former south pole which had been connected 

 with the zinc plates having now acquired north polarity; and 

 ^nall cases, that end of a needle which wasconnected with the 

 ^^c plates of the instrument, acquired north polarity, when 



A steel needle free from magnetism, 



left 



enc 



y^^thin a tube of glass four inches long and an eighth of an 

 ^fich in diameter. This glass tube was then placed within 

 a tube of lead, ^n^ the lead tube a;;ain enclosed in one of 

 la^s,around which was placed a spiral of brass wire, wound 

 ■ omltft to right; the ends of the spirals being connected with 

 *be opposite galvanic poles — Tlie plates were immersed 

 a^d suffered to remain in the fluid during: half a minute 



