84 EMPLOYMENT OF ELECTRICITY 



exertions received the kind and flattering appro- 

 bation of the Edinburgh Review, Lancet, the late 

 Dr. Pereira, and others of the profession ; and the 

 able suggestions of Dr. Barnes led ultimately 

 to a still further reduction in the size of the 

 instrument, for the sake of rendering it more 

 portable and efficient for general as well as for 

 specific purposes, which improvement is again 

 most gratifyingly acknowledged by the scientific 

 world. I have the honour of exhibiting one of 

 these instruments to the Society this evening, 

 as modified to suit the requirements of the den- 

 tal profession ; but whilst it may appear to me 

 to combine every requisite, the experience of 

 others may suggest modifications and appliances 

 to which it will afford me great pleasure to 

 listen. 



I may explain that the chief scientific features, 

 and if I may be allowed the term, I will say, 

 the chief advantages of the instrument, are as 

 follows : — 



1st. The exciting battery (Smee's) is, I believe, 

 smaller than any yet used, the silver plate being 

 only three inches long, and about one inch wide, 

 and the quantity of dilute acid required to excite 

 it little more than a wine-glassful. Small as this 

 battery is, the magnetism produced by it in the 

 iron core is sufficient to sustain several pounds' 

 weight at one end. 



2nd. The amount of magnetism thus produced 



