3813*] Dr. Joseph Tnestley, m 



discoveries made by each author being arranged almostly exactly 

 according to the time in which he wrote. Dr. Priestley seems 

 to have placed the books in chronological order^ and to have 

 read and abridged them in that order^ and never afterwards to 

 have altered what he wrote. Now in giving an account of a 

 science, it is very seldom that the clironological order is the best 

 suited to the detail of facts. Some of the first principles are 

 usually very late in making their appearance. Hence many of 

 the early discovered facts receive their interest and explanation 

 from facts discovered long afterwards ; and unless the whole be 

 arranged so as to make the facts bear upon each other, it is to a 

 great degree destitute of interest. I confess that this was the 

 feeling which attended my first perusal of the History of Elec- 

 tricity. The book, however, possesses value ; as it collects in 

 one view the scattered facts which were spread through a great 

 variety of books which preceded him, and which at that time it 

 was difficult to obtain. The great eclat which Electricity had 

 at that time acquired, owing in a great measure to the very 

 splendid experiments made by the Royal Society, chiefly I believe 

 in consequence of the influence of Dr. Watson, the discovery of 

 the identity of lightning and electricity by Dr. Franklin, and the 

 discovery of the Leyden phial and its wonderful effects by Mus- 

 choenbroek — the great eclat produced by these splendid disco- 

 veries gave an unprecedented popularity to electrical pursuits. 

 Every body was anxious to be acquainted with the facts ; and as 

 no treatise on the subject had appeared at all comparable to that 

 of Dr. Priestley, we need not be surprised that it became 

 popular, and that the reputation of its author suffered a cor- 

 responding exaltation especially as his book contained several 

 original experiments, and as he continued to prosecute the subject 

 for some years afterwards. Dr. Priestley led to various important 

 discoveries in electricity, by introducing a change in the appa- 

 ratus, substituting powerful machines and large batteries to -the 

 very puny ones formerly in use. Mr. Nairne's machine, by far 

 the simplest and best in use, before the introduction of the plate 

 ones by Cuthbertson, was in some measure owing to Dr. 

 Priestley, as he suggested changes and improvements upon 

 which that consummate artist went to work, and soon brought 

 the machine to the requisite simplicity. 



The principal discoveries in electricity made by Dr. Priestley 

 were the two following: 1. Charcoal is a perfect conductor of 

 electricity. 2. All metals, without exception, may be oxydized 

 by passing through them a sufificiently strong electrical charge. 

 Me made several other minor discoveries ; but in this general 

 sketch 1 do not think it worth while to enumerate them. To 

 the theory of electricity he made no additions nor improvements 

 whatever. Indeed, his turn of mind, and his precipitancy, did 



