I JOSEPH PRIESTLEY 33 



Newton had laid the foundation of a mechani- 

 cal conception of the physical universe: Hartley, 

 putting a modern face upon ancient materialism, 

 had extended that mechanical conception to psy- 

 chology; Linn^us and Haller were beginning to 

 introduce method and order into the chaotic 

 accumulation of biological facts. But those 

 parts of physical science which deal with heat, 

 electricity, and magnetism, and above all, 

 chemistry, in the modern sense, can hardly 

 be said to have had an existence. ISTo one 

 knew that two of the old elemental bodies, air 

 and water, are compounds, and that a third, fire, 

 is not a substance but a motion. The great 

 industries that have grown out of the applica- 

 tions of modern scientific discoveries had no 

 existence, and the man who should have foretold 

 their coming into being in the days of his son, 

 would have been regarded as a mad enthusiast. 



In common with many other excellent persons, 

 Priestley believed that man is capable of reaching, 

 and will eventually attain, perfection. If the 

 temperature of space presented no obstacle, I 

 should be glad to entertain the same idea; but 

 judging from the past progress of our species, I 

 am afraid that the globe will have cooled down 

 so far, before the advent of this natural millen- 

 nium, that we shall be, at best, perfected Esqui- 

 maux. For all practical purposes, however, it is 

 enough that man may visibly improve his condi- 



