Magnetic Effects of Dr. Hare's Calor'motor. 357 



AiiT. XXI, — Xotke of Magnetic effects produced^ hj Dr. 



Harems Calorimotor ; by George T* Bowex, of Provi- 

 dence^ 



In Vol. V. p, 352 of the Edln. Phil. Journal, is a de- 

 scription of an electro-magnetic apparatus by Prof, Moll of 

 Utrecht. After having given a description of the instru- 

 ment, that gentleman observes, " A remarkable feature in 

 the effect of this spiral voltaic apparatus, is the strong adhe- 

 sion of iron filings to the conductive wire. If the zinc plate 

 be new, or well cleaned, the acid strong, ?nd of course the 

 galvanic process going on with energy, then if iron filings, 

 on a paper, are brought backward and forward, under, and 

 near to the horizontal conductive wire of copper, the iron 

 filings will begin to stand erect as if in the vicinity of a load- 

 stone, and they will even adhere strongly to the copper 

 ^ire when brought into contact with it." These observa- 

 tions appearing to me to be interesting, I was desirous of 

 Seeing what would be the effect produced by pVesenting 

 Jfon filings to the wnre which connects the opposite poles of 

 the calorimotor of Doct, Hare. The results of the experi- 

 nients which were performed with this instrument are as 

 lollows : — A large copper wire, about one foot in length, 

 ^vas bent in the form of a semi-circle, and its ends connect- 

 ed by means of small vaces to the opposite poles of the ca- 

 'orimotor. The instrument was then immersed in the 

 ^veak acid solution- On bringing a paper containing iron 

 filings into the vicinity of the copper, which had already 

 become hot, the filings began to stand erect, and when 

 brought into contact wnth the wire they were powerfully at- 

 tracted by it; adhering to it, and forming a fringe upon its 

 surface. The calorimotor was then raised out of the dilu- 

 ted acid, and it was observed that the filings dropped from 

 the connectini^ wire, the instant the instrument left the sur- 

 face of the fluid. This experiment was often repeated ; 

 (the size of the connecting wire being varied,) and always 

 ^ith the same results. A platlna wire was then bent as in 

 t'ie above experiment, and its ends connected with the op- 

 posite poles of the calorimotor. Upon immersing the plates, 

 ^nd bringing the iron filings on a paper, near to, and into con- 

 tact with the platina, they were powerfully attracted, ami 



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* la the laboratory of Yale Colkg"^. 



