POPULAR SCIENCE. 15 



of knowledge once abstract, ultimately applied to popular 

 utility. The discovery of phosphorus is one of many which 

 have been evolved from labours of the alchemist. It was dis- 

 covered by Kunkel, and by chance. But for the incentive of 

 the philosopher's stone and universal elixir, phosphorus might 

 not perhaps have been discovered until our own days. It was 

 first obtained from animal fluids, next from bones ; ultimately, 

 when the supply of bones ran short, attention was turned to 

 the mineral phosphate of lime of Estremadura, from which sub- 

 stance nearly all the phosphorus of commerce is now extracted. 

 A valuable essay illustrating our topic might be composed 

 on the subject of the discoveries to which alchemy, or the 

 belief in metallic transmutation, gave rise. At different 

 epochs of human advancement the mind of man is ruled by 

 different incentives; but one the love of immediate gain 

 pervades all epochs. Experimental science has now at- 

 tained such development, that it affords ample scope for in- 

 tellectual exercise. Day by day it more nearly approaches to 

 the exactness of mathematical science, in the study of which 

 numerous men of high intellectual endowments, from the 

 time of Euclid and Archimedes down to the time when we 

 live, have found solace. It was not thus in respect to che- 

 mistry and other experimental sciences until lately. Even 

 going back a century, chemistry barely afforded any field for 

 rigid intellectual study at all ; but now, owing to the formu- 

 larisation of its known laws, much advance in the science may 

 be achieved by book-work alone, without the need of actual 

 experiment. The question indeed arises, whether the next 

 great chemical discovery will not appertain to him who, hav- 

 ing competent mathematical knowledge, applies himself to 

 generalise the weighings and measurings already done and 

 recorded, rather than to the industrious laboratory- worker. It 

 takes long in the education of the human mind before men 

 come to put faith in the belief that the unravelling of truth 

 is valuable for its own sake alone ; and the belief once ere- 



