NATURAL PHILOSOPHY. 115 



means, and by the simplest of all batteries, the telegraph clerks sent 

 several messages to and fro from England to France. The next 

 experiment was similar to this, only a larger piece of zinc and a 

 larger piece of silver were introduced into the mouth of the operator. 

 The result was an improvement of the signals. On a subsequent 

 occasion, in the presence of a large number of scientific gentlemen, 

 the instruments with the miniature batteries transmitted all the com- 

 mercial messages, prices of stocks, funds, &c. It was thought that 

 during these operations the miniature battery would become exhausted ; 

 on the reverse, it improved, and seemed perfectiy to maintain its 

 character. 



An improvement of the well-known Grove's batteries has been 

 recently introduced on one of the telegraphic lines between Boston 

 and New York. It has been found that in the battery, if instead of 

 immersing platinum strips of one or two square inches in the exciting 

 fluid, platinum wire be used, an equally powerful effect is produced. 

 If the zinc element be as small, it will, so long as it lasts, be of equal 

 avail. But since the zinc is constantly and necessarily decomposed 

 by the action of the acid, so great a reduction in size is not advisable. 

 But the platinum never wastes. In the prime cost of a battery, the 

 platinum is by far the largest item, and by its reduction, the expense 

 of a battery is diminished about one-half. In order to retain the pla- 

 tinum in its place, the end of the wire that is immersed in the fluid, 

 may terminate in a bead, either of platinum or of glass. The weight 

 of this bead will counteract all tendency of the wire to bend or curl, 

 and will keep it constantly immersed in the fluid. The reduction in 

 the size of the plates, does not modify, in the least, the nature of the 

 working current. 



The London Athenaeum gives the following account of a new gal- 

 vanic batterv recently exhibited in that city by Mr. Marty n Roberts. 



f tf if m 9 



The battery consisted of fifty plates of tin about six inches by four, 

 each plate being adjusted between two plates of platinum of the 

 same size. These were placed in stone-ware cells about two feet 

 deep, which were filled with diluted nitric acid. The object of these 

 deep cells was, to obtain a marketable product which should be suffi- 

 ciently valuable to cover the cost of the agents employed to effect the 

 development of electricity. The upper stratum of nitric acid acts on 

 the tin, and forms with that metal an oxide, which falls off from the 

 plate the moment it is formed, and is precipitated as a hydrated oxide 

 of tin to the bottom of the cell. This oxide is combined with soda ; 

 and as stannate of soda is extensively employed in dyeing and calico 

 printing ; it is stated that this product will yield a profit of 20 per 

 cent, on the cost of the battery but this is a point which we are not 

 at present in a position to determine. The electrical action of the 

 fifty pairs of plates was considerable. The current was employed to 

 exhibit the electrical light, and the effects produced were certainly 

 very brilliant. It was not possible to compare it with the result 

 obtained from a Grove's battery, but we judge their powers to be 

 nearly equal. An experiment made on the decomposition of water 

 11 



