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May 8th, 1848. 



REV. HUMPHREY LLOYD, D. D., President, 

 in the Chair. 



Sir Robert Kane read the following account, by the Rev. 

 Professor Callan, of Maynooth, on the use and construction of 

 a new form of the Galvanic Battery : 



" In a paper published in the August Number of the 

 London Philosophical Magazine, I described several experi- 

 ments, which clearly prove that, as a negative element of the 

 nitric acid battery, lead coated with chloride of gold or platina, 

 or with borax dissolved in dilute acid, is superior to platina, and 

 that cast iron is fully as powerful as platina. I have since 

 compared, in various ways, the power of a cast-iron battery 

 with that of a Grove's of equal size. The cast iron was ex- 

 cited by a mixture consisting of about four parts of sulphuric 

 acid, two of nitric acid, and two of nitre dissolved in water. 

 The platina was excited by equal parts of concentrated nitric 

 and sulphuric acid. The zinc plates of both batteries were 

 excited by dilute sulphuric acid of the same strength. The 

 cast-iron battery was considerably superior to Grove's, in its 

 magnetic power, in its heating power, and in its power of pro- 

 ducing decomposition. The magnetic effects of the two bat- 

 teries were compared by means of a galvanometer and of a 

 small magnetic machine. Grove's produced a deflection of 

 82° ; the cast iron caused a deflection of 85°. When the vol- 

 taic currents of the two batteries were sent simultaneously in 

 opposite directions through the helix of the galvanometer, the 

 current from the cast-iron battery destroyed the deflection 

 caused by Grove's, and produced an opposite deflection of 60°. 

 In the magnetic machine the cast-iron battery produced fifty 

 revolutions in a minute ; Grove's produced only thirty-five in 

 the same time. 



" The superiority of the beating power of the cast-iron 



I 



