454 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



familiar blue solution, lies in a tolerably distinct stratum at the 

 bottom. Care must be taken not to introduce so much of the 

 copper sulphate as to mingle quite up to the zinc plate, as in such 

 case local action will result, and the copper will be deposited on 

 the zinc, causing considerable mischief. To prevent the chance 

 of this the plates are placed a considerable distance apart, which 

 increases the resistance of the battery. 



Dr. Bradley stated that he had tested this in his own practice 

 as a manufiicturer and fitter up of such apparatus, and commended 

 it highly. He had found this battery less efficient, cup for cup, 

 than the Grove, but the result was a greater economy. He esti- 

 mated 100 of these cups equal to forty of the Grove, but the cost 

 of maintenance of the whole was only about one-fifth. The con- 

 sumption of materials w^as only one-half as great as by the very 

 economical battery known as Chester's, or the Chromic Acid 

 battery. 



Smee's battery was very efficient in depositing metals for elec- 

 tro metallurgical purposes, but was too irregular and too fiery to 

 be recommended for telegraphing. It was very little used for 

 that. 



In practice, telegraphing was very much affected by the state 

 of the weather. lu good weather, 100 cups of the Hill battery, 

 above described, operated eight lines — meaning eight wires — iii 

 the United States Company's office, while in bad weather it will 

 work but two properly. 



Mr. Stetson, the Secretary, said that imperfect insulation afiected 

 the efficiency of telegraphic communication very materially. Evea 

 ivebs produced by insects in some otherwise good forms of insu- 

 lators, militated strongly against their success in wet weather, 

 particularly in gales of wind. Every spider's web extending 

 between the wires and the neighboring conducting surfaces serves 

 as an efficient conductor to lead away the current. There is a loss 

 at every telegraph pole. 



After further debate on telegraphic improvements, the Associa- 

 tion adjourned. 



