Highly practical nature of research. 47 



comprehension. A man who discovers knowledge 

 for the use of invention is quite as practical a person 

 as he who converts that knowledge into inventions 

 fit for practical uses. The men who thus lead 

 practical men must be practical themselves. Scien- 

 tific discoverers may be considered the most practical 

 men in existence, because their labours give rise to 

 greater and more numerous practical results than 

 those of any other persons. The discovery of a 

 single substance, such as oil-of-vitriol, or washing- 

 soda, has led to the formation of many valuable 

 inventions, patented or otherwise, and to the estab- 

 lishment of thousands of manufactories. It is well 

 known also that scientific discoverers are ardent 

 lovers of truth, and are therefore very willing to 

 communicate their knowledge for the good of man- 

 kind, and that manufacturers, men of business, and 

 others, not unfrequently obtain from them and from 

 their published researches, information of great 

 value to themselves without even expecting to pay 

 for it ; forgetting that a scientific man may com- 

 municate in a passing remark, information which 

 cost him years of labour to obtain. 



Some persons also think that science is changeable 

 and uncertain that the discoveries of one genera- 

 tion are disproved by those of another, because they 

 occasionally see scientific theories altered and super- 

 seded. But the real truth of the case is that the 

 changes in the aspect of science which we continually 

 witness do not often result from alterations in our 



