422 Prof. Zantedeschi on the Motions presented hy Flame 



ble fluids at the zero of the scale of action among magnetic 

 and diamagnetic bodies. On the 21st of September 1847, at 

 the Physical Section of the Ninth Italian Scientific Congress 

 in Venice, Padre Bancalari, Professor of Physics in the Royal 

 University of Genoa, read a memoir on the universality of 

 magnetism ; and the argument was considered by philosophers 

 to be of such importance, that a desire arose to verify chiefly 

 the action of magnetism on expansible fluids. It was an- 

 nounced by the Reporter Belli at the sitting of the 27th of 

 September, that it had been proved in the presence of various 

 philosophers that, on the interposition of a flame between the 

 two poles of an electro-magnet, it was repulsed at the instant 

 the electric current was closed, to return to the first position 

 the instant it was broken. This discovery received well- 

 merited applause in the sitting of the 28th of September, 

 from the General Secretary and the Secretary of the Section of 

 Physics. A wish was expressed by some to witness the experi- 

 ment of Bancalari; and a Daniell's apparatus having been got 

 ready, often elements eighteen centimetres each in dimension, I 

 endeavoured to repeat the experiment in the Cabinet of Physics 

 of the Royal Imperial Lyceum of Venice; but I did not chance 

 to see the asserted phaenomenon. My temporary magnet 

 had the power of sustaining above 48 kilogrms. weight; but 

 as my principle is, that a negative argument never destroys a 

 positive one, I for my further information requested the 

 machinist Cobres to give me the particulars of the apparatus; 

 Belli not having treated of these in his report, and they having 

 escaped Prof. Zambra, the Secretary of the Section. I knew 

 that the two pieces of soft iron, which constituted the inter- 

 rupted anchor, were perforated in the axial direction. I 

 suspected that the repulsion of the flame was not the immediate 

 effect of the magnetism, but of two currents of air issuing from 

 the apertures of the perforated keeper generated by a vorticose 

 movement produced by the magnetism, as the celebrated 

 Faraday had observed in liquids* ; and I was confirmed in this 

 suspicion by the negative experiment which I had instituted in 

 Venice with solid pieces. On arriving in Turin, I communi- 

 cated my doubts to the well-known mechanicians Jest, father 

 and son, who to their professional abilities unite a rare courtesy. 

 They soon furnished me in their laboratory with a Bunsen's ap- 

 paratus, and constructed terminal pieces of soft iron forming the 

 interrupted anchor, both solid and pierced, of a parallelepipe- 

 don and cylindric form, as I pointed out to them ; and I have 

 repeated the experiments in their company : the temporary 



* RaccoHa, cited above, t. ii. Relazione dell' influenza delle forze elet- 

 triche e magnetiche sulla luce ed il calorico. 



