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HISTORY OF

[ 1780 — 85 .

to sacrifice such resentment as rose among them to thegood of the general cause in which they felt themselvesequally embarked; for although some individuals amongthem have heretofore indulged their feelings by appeal-ing to the public when they imagined the welfare of thebody at large was in danger, they never once attemptedto convert the Meetings instituted for the advancementof knowledge into assemblies of debate and contro-versy.”

The year 1784 is certainly a memorable one inthe annals of the Royal Society . We have seen howit was marked by violent dissensions, foreign to mat-ters of science; we have now to examine the scien-tific events of that year, in relation to a discoverywhich has of late given rise to much discussion, andunduly harassed the scientific world. I allude tothe Composition of Water, the discovery of which isattributed by some to Cavendish, and by others toWatt 16 . The reader will perhaps arrive at the con-clusion, that these great men made the discovery inde-pendently of each other.

It may be proper to premise that in 1776, Voltafired inflammable air (hydrogen gas mixed with com-mon air) by the electric spark 17 . In 1778, Macquer observed, that moisture consisting of pure water wasformed when inflammable air was burnt in a closevessel full of common air. But this water was sup-. posed to be merely the fluid which was held in sus-

16 I am indebted to Professors Graham and Miller, and to Mr.Brande, for their kindness in revising the following pages relatingto this subject.

17 See letter from Yolta to Priestley, dated Como, Dec. 10,1776, in Priestley’s Exp. on Air.