PRIESTLEY'S DISCOVERY OF OXYGEN GAS. 389 



and lastly, that the atmosphere itself, far from being, as the ancients 

 had supposed, a simple homogeneous mass, contained this substance as 

 its active principle, mingled with four times as much of another differ- 

 ent body. 



Here, before explaining the consequences of this great discovery, 

 and showing the position in which it stands, I may be permitted to 

 spend a moment in relating the melancholy but interesting history of 

 its author. It is a lesson which ought not to be lost. Born the son of 

 a tradesman, who died while he was young, and left him very poor, 

 his early manhood was spent in the useful but tedious duties of a vil- 

 lage school-master. His attention being turned to theology, he subse- 

 quently became the pastor of a Presbyterian church. We must not 

 impute it to mental weakness, but rather to a pursuit of the truth, that 

 in succession he passed through many phases of religious belief, and 

 four different sects, the Presbyterian, Arrainian, Arian, and Unitarian, 

 received him as a votary. This is not the occasion nor the place to ex- 

 plain the causes that led him in this course. It is only for us to judge 

 of so great a man with charity. But, imbued as he was with a deep 

 religious sentiment, and feeling that even the most exalted objects of 

 this life are not to be compared with the importance of another world, 

 he regarded his philosophical pursuits as a very secondary affair, and 

 gave much of his time and talent to controversial theology. He 

 seems to have come to the conclusion that it was incumbent on him to 

 make a religious war. As his biographer says, " Atheists, Deists, 

 Jews, Arians, Quakers, Methodists, Calvinists, Catholics, Episcopa- 

 lians, had alike to combat him." In more than a hundred volumes 

 which he printed, each of these found an adversary of such force and 

 vigor (and it was impossible with such a man that it could be other- 

 wise), that their ablest theological writers were overmatched. By the 

 established Church of Enojland he came to be reejarded with such 

 feelings, that instances occurred in which those who had successfully 

 answered him were rewarded with the highest dignities; a circum- 

 stance which gave origin to his remark that he appointed the Bishops 

 of England. 



But this was not all. The first French Kevolution broke out, and, 

 his ardent mind imbibing with enthusiasm the seductive doctrines of 

 the times, he added to his religious disputes those of a political par- 

 tisan. As the different sects had in succession stood in fear of him, 

 so now the government took alarm ; it knew his philosophical reputa- 

 tion and ability. The story is a sad and short one. A mob assembled 

 round his dwelling, which they committed to the flames ; the houses 

 of those who were known to be his friends shared the same fate; he 

 narrowly escaped with his life ; and for three days one of the chief 

 cities of the nation was the scene of riot. All his philosophical instru- 

 ments, most of them constructed by himself, his manuscripts, his 

 library, the fruits of a frugal life, were destroyed; and, eventually 



