22 



tliose still in use were developed hy Bergmaiin and hy other eonteuiporaiies of 

 Lavoisier who still held entirely to the old theories. The tjiiantitative niethod 

 was "in the air" as it were, and was coming into more and more extended use iii 

 the hands of many different chemists. And, even after Lavoisier's views were 

 generally accepted, (juantitative results were usually very inaccurate till some 

 time after Dalton's atomic theory had given a sharp means of control. La- 

 voisier's greatness was not so miicii in the introduction of a new method, as in that 

 wonderful insight whicli enaljled him to see through tlie apjiearances on llie sur- 

 face and find the real reasons which lay beneath. 



The beginning of his most valuable work seems to have been made in 1772. 

 when he was not yet thirty years of age. In a short note written at this lime and 

 published in 1778, he states that the oxidation of metals and also the combustion 

 of phosphorus and sulphur is accompanied by an increase of weight and by the 

 absorption of a large amount of air, also that on the reduction of metallic oxide.s 

 a large amount of gas, or "air" is evolved. In these crude and imperfect state- 

 ments, we see the germ of all his greatest discoveries. In 1774 he described more 

 accurately his experiments with tin. He placed the metal in a retort, sealed it 

 hermetically and weighed the whole. He then heated the retort till the tin was 

 oxidized, and then weighed the whole again, showing that there was no change in 

 weight. On opening the retort, air entered, and there was an increase of vveight- 

 which he says was exactly e(Hial to the gain in weight of the tin due to oxidation. 

 We know that this could not have been strictly accurate, for oxygen had been ab- 

 sorbed, and air, which is specifically lighter than oxygen, had entered, but we see 

 once more the great power which the man had of drawing correct conclusions from 

 imperfect data. A chemist of some standing has recently said, "that it is not the 

 province of science to explain anything," and "that the business of science is to 

 describe phenomena in a simple manner, to seek actual relations between measure- 

 able quantities, to deal only with things which can be handled and measured." 

 How erroneous and imperfect such a view of the province of science is, was never 

 better illustrated than in the present case. Essentially the same fact in almost 

 all of its details had been observed by Boyle one hundred years before, and many 

 others had observed that metals increase in weight when oxidized. The fact alone 

 was liarrcu, the fact in coujunctiou with its correct explanation liccame fruitful 

 in wdiiderful scientitic dexclopments. 



In tliese first experiments Lavoisier does not seem to liave recognized but 

 wliat air, as a whole, was al)sorbed in processes of oxidation and coiiibustion. On 

 August 1, 1774, Priestley, Jn England, discovered oxygen gas, and visiting Paris 



1. J. E. Trevor, Jr., Am. Chem. Soc, m, 520. 



