THE USEFUL AND THE PRACTICAL. 145 



ginally included only certain methods of partitioning ground 

 and laying out buildings. The properties of the scales and 

 the lever, involving the first principle in. mechanics, were 

 early generalized under the stimulus of commercial and 

 architectural needs. To fix the times of religious festivals 

 and agricultural operations, were the motives which led to 

 the establishment of the simpler astronomic periods. Such 

 small knowledge of chemical relations as was involved in 

 ancient metallurgy, was manifestly obtained in seeking how 

 to improve tools and weapons. In the alchemy of later 

 times, we see how greatly an intense hope of private benefit 

 contributed to the disclosure of a certain class of uniformities. 

 Nor is our own age barren of illustrations. &quot; Here,&quot; says 

 Humboldt, Avhen in Guiana, &quot; as in many parts in Europe, the 

 sciences are thought worthy to occupy the mind, only so far 

 as they confer some immediate and practical benefit on 

 society.&quot; &quot; How is it possible to believe,&quot; said a missionary 

 to him, &quot; that you have left your country to come to be de 

 voured by mosquitoes on this river, and to measure lands 

 that are not your own.&quot; - Our coasts furnish like instances. 

 Every sea-side naturalist knows how great is the contempt 

 with which fishermen regard the collection of objects for the 

 microscope or aquarium. Their incredulity as to the possible 

 value of such things is so great, that they can scarcely be 

 induced even by bribes to preserve the refuse of their nets. 

 Nay, we need not go for evidence beyond daily table-talk. 

 The demand for &quot; practical science &quot; for a knowledge that 

 can be brought to bear on the business of life joined to the 

 ridicule commonly vented on scientific pursuits having no 

 obvious uses, suffice to show that the order in which laws 

 are discovered greatly depends on the directness with which 

 they affect our welfare. 



That, when all other conditions are the same, obtrusive 

 relations will be generalized before unobtrusive ones, is so 

 nearly a truism that examples appear almost superfluous. If 



