The Rev. N. J. Callan on a new Voltaic Battery. 85 



I feel confident that the latter may, without any diminution 

 of power, be substituted for the former in Smee's battery. 

 Cast iron does not take the coating of platina powder (at least 

 until the hard surface is worn away) so well as lead or silver, 

 and on that account it does not act as powerfully as either. 

 But I have found zinc and cast iron excited by dilute sul- 

 phuric acid as constant in their action as zinc and platinized 

 lead. A platinized lead, or cast iron plate six inches square, 

 may be had for the twelfth part of the cost of a platinized 

 sheet of silver of the same size. 



From the experiments which have been described, I infer, 

 first, that a battery superior in power to Professor Grove's 

 nitric acid battery may be made by substituting platinized 

 platina or lead for platina, and nitrosulphuric acid and nitrate 

 of potash for nitric and sulphuric acid; and secondly, that a 

 battery equal in power to the nitric acid battery may be con- 

 structed by the substitution of cast iron for platina. 



The advantage of what I may call the nitre platina battery 

 over the nitric acid one is, that the expense of working the 

 former is, as has been already stated, considerably less than 

 that of working the latter. 



The advantage of the cast iron or platinized leaden batteries 

 over Professor Grove's is, that they are far less expensive in 

 their construction. A plate of cast iron or platinized lead 

 may be had for a shilling, whilst a platina plate of the same 

 size will cost nearly three pounds. Besides, a cast iron or 

 platinized lead battery may be worked by a mixture of nitre 

 and sulphuric acid for one hour for about the tenth part of 

 the expense of working a Grove's battery for the same time. 



The cheapness of cast iron and platinized lead will enable 

 every one to procure a powerful voltaic battery. A platinized 

 lead battery is about fifteen times as powerful as a common 

 Wollaston battery of the same size. A cast iron battery is a 

 little less powerful than the platinized lead one; but I prefer 

 the former, because the cast iron does not require to be chromed 

 or platinized. I am now preparing two large cast iron bat- 

 teries for the College : one will contain about thirty-three 

 square feet of zinc and sixty-six of cast iron, the other will 

 contain eighty square feet of zinc and a hundred and sixty of 

 cast iron. These batteries will be more powerful than any 

 battery ever constructed. The expense will be very mode- 

 rate; for the zinc plates and Wedgwood troughs of our for- 

 mer batteries will answer for the new ones. 



Maynooth College, July 3, 1847. 



