~ 
236 Seventifie Labors and ‘Character of 
the water that appeared ; and it seemed decisive in favor of this con- 
clusion, that the quantity of oxygen contained in the water, was ex-- 
actly that which existed in the oxide of tin. This last fact left.a strong 
impression in favor of Davy’s hypothesis, and against: the idea sup- 
ported by Murray, that the water present was the same as had before 
existed in the muriatic acid, and which was released when the acid 
went into combination with the base. But the doctrine of equivalent 
quantities has proved, that the quantity of oxygen which is contained 
in the water produced in this experiment, would be precisely the 
same, whether derived from the oxide or the acid.* 
In this manner did the controversy proceed, each successive paper 
producing arguments which seemed invincible in favor of the writer ~ 
and against his antagonist, while every thrust was parried with the 
dexterity of the most accomplished masters. Nor did it seem pos- 
sible to settle the question, until the discovery of iodine so much 
strengthened the hypothesis of Davy, that almost every chemist of 
the age from that period has adopted it. ) 
It has been said of Sir Isaac Newton, that he was so well acquaint-- 
ed with nature and understood her analogies so fully, that he always 
Suessed right. The increasing probability which has followed many of 
the novel hints and suggestions thrown out by our philosopher, at a very 
early period, (for example those respecting the identity of chemical 
and electrical attractions, the geological agencies of the metallic bases 
of the earths and alkalies; and the simple nature of chlorine,) almost 
persuades us to apply to Sir Humphry Davy a similar remark. 
It is hardly possible to review the history of the foregoing contro- 
versy, without being strongly impressed with the delusive nature of 
hypotheses in general, if by hypothesis we understand a supposition 
of which there is no other proof, than that it explains all the phenom- 
ena to which it is applied. The two hypotheses of electricity as well 
_ as those respecting oxy-muriatic acid, applying as they respectively 
do toa great multitude of facts, while we know that one or the other 
of them must be false, prove the danger of relying on such a con- 
formity of our supposition with facts, as a criterion of their truth. 
_ An the year 1812, at the age of 32, Davy stood on one of the 
proudest heights of science. By his extraordinary discoveries he 
had extended the empire of man over matter ; by strong powers 
of reasoning united with great ingenuity of research, he had changed 
* Murray’s Elements, 6th edition, II. 797. 
