1 7 6 HER OES OF INVENTION AND DISCO VER Y. 



grows in vain ; but that, from the oak of the forest to the grass 

 of the field, every individual plant is serviceable to mankind ; 

 if not always distinguished by some private virtue, yet making 

 a part of the v/hole which cleans and purifies our atmosphere. 

 In this the fragrant rose and deadly nightshade co-operate ; nor 

 is the herbage nor the woods that flourish in the most remote 

 and unpeopled regions unprofitable to us, nor we to them, con- 

 sidering how constantly the winds convey to them our vitiated 

 air, for our relief and for their nourishment. And if ever these 

 salutary gales rise to storms and hurricanes, let us still trace 

 and revere the ways of a beneficent Being, who, not fortuitously 

 but with design, not in wrath but in mercy, shakes the water 

 and the air together, to bury in the deep those putrid and 

 pestilential efiluvia which the vegetables on the face of the 

 earth had been insufficient to consume." 



In perusing the works of Priestley, it is impossible to fail 

 being struck with his intense love of truth. In his scientific 

 note-books, he registered every fact as it appeared to his 

 senses ; in his political and theological \\Titings, he fearlessly 

 states his opinions as they are brought out by his cross-examina- 

 tion of his own thoughts and meditations ; and that liberty ot 

 independent thought which he claims for himself he determinedly 

 demands for others. In his scientific career, his object was 

 uniformly to question Nature by every possible experimental 

 investigation, and to state its results as he obtained them. 



"Whether we view him," says Professor Thomson, "as a 

 pneumatic chemist, a theologian, an electrician, a historian, a 

 politician, his writings bear the impress oi an original mind, 

 uncontrolled by any tendency to follow in beaten tracts, but 

 constantly panting for new fields of investigation. It will ever 

 remain a stain upon the name of Enpland, that this noble- 



