114 ELECTRICITY. 



uses of ife, are well worthy to be put in juxtaposition with the discoveries of 

 Newton respecting the analysis and properties of light. How different, how- 

 ever, was the position of these two great discoverers and benefactors of the 

 human race ! One brought to bear on the subject of his inquiry a mind early 

 disciplined in scientific investigation, a memory stored with profound mathe- 

 ( matical erudition, faculties rendered more acute and strong by the severe studies ' 

 ' exacted from all aspirants to academical honor and office in the universities of 

 the old countries, zeal awakened, emulation stimulated, and enthusiasm kindled 

 by associates, among whom were included all that was most distinguished in 

 the physical sciences ; the other, first a tallow-chandler's apprentice, and next 

 a poor printer's boy, unschooled, undisciplined, self-informed, having nothing to 

 aid him but the inborn energy of his mind, separated by an ocean three thou- 

 sand miles wide from the countries which alone were the seats of the sciences, 

 and where alone those aids and encouragements derivable from the society of 

 others engaged in like inquiries could be obtained. Such was the individual 

 whose researches we must now briefly notice. The series of letters in which 

 he embodied the details of his experiments, and developed the laws which re- 

 sulted from them, were continued from 1747 to 1754, and were subsequently 

 collected and published. 



" Nothing," says Priestley, " was ever written upon the subject of electricity 

 which was more generally read and admired in all parts of Europe than these 

 letters. There is hardly any European language into which they have not 

 been translated ; and, as if this were not sufficient to make them properly 

 known, a translation of them has lately been made into Latin. It is not easy 

 to say whether we are most pleased with the simplicity and perspicuity with 

 which these letters are written, the modesty Avith which the author proposes 

 every hypothesis of his own, or the noble frankness with which he relates his 

 mistakes when they were corrected by subsequent experiments."* 



In the analysis of Franklin's discoveries, it is necessary to distinguish care- 

 fully fact from hypothesis, and to separate the great natural laws which he 

 brought to light, the truth and reality of which can never be shaken, based, as 

 they are, on innumerable observed phenomena, from the theory by which these 

 phenomena and their laws are attempted to be explained by him ; which latter, 

 though marked by great sagacity and ingenuity, and adequate to the explica- 

 tion of most of the ordinary effects of electricity, has been found insufficient to 

 represent the results of subsequent researches, and has been generally super- 

 seded by another theory, which will be noticed hereafter. 



The first step made by this philosopher in the brilliant series of discoveries 

 by which he rendered his name so memorable, was one which produced a 

 material influence on his subsequent proceedings, since it formed the founda- 

 tion of his celebrated hypothesis of positive and negative electricity, which 

 served him as the link by which many scattered facts might be grouped and 

 connected, and as a clue to the development of new and unobserved phe- 

 nomena. To reduce to the most brief, simple, and general terms, the expres- 

 sion of the first fruit of his observations, it may be said to consist in the es- 

 tablishment of the general principle, that when electricity is excited by the 

 mutual friction or attrition of any two bodies, both these bodies become elec- 

 trified ; and if both are insulated they will continue to be so electrified. They 

 will, however, be in different electrical states, since, if moveable, they would 

 attract and not repel each other ; but, nevertheless, each of them will exhibit 

 in relation to other bodies not electrified, the same properties. Thus sparks 

 may be drawn indifferently from either ; and each of them may be de-ekctriscd, 



