356 HISTORY OF CHEMISTRY. [LECTURE XVI. 



possible to extend the system to substances containing rings, 

 still there is much that is good and valuable in the principles 

 that have been advanced. 



With the foregoing observations I may be permitted to 

 conclude these lectures. I shall be gratified if the matters that 

 have been discussed should prove to be of value in conveying 

 an outline of the history of our science ; and, in any case, I 

 hope that the lectures may serve as a stimulus to independent 

 study. There are few things which operate more advantageously 

 in the latter direction than a survey of the past. We recognise 

 that progress is only possible with the united activity of many 

 workers; we realise that even the smallest contribution is not 

 useless ; and we are led to exercise our own small capacities 

 in the hope that they also may increase, by a drop, the tide of 

 general knowledge. 



^ OF THE 



UNIVERSITY 



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