APPLICABLE TO MATHEMATICS, &C. 333 



researches thus far, they would be attended with 

 great labour and expense ; the latter prevents 

 entirely the more humble inquirer after nature's 

 truths, from being able to hold a communion 

 with those truths that are far removed from the 

 ordinary observations of man. 



A beautiful exemplification of this mode of 

 obtaining from nature her profound, yet simple 

 treasures, may be found in the writings of Dr. 

 Dalton. In his Meterological observations, page 

 18, he states that "one universal effect of fire, is 

 its expanding or enlarging those bodies into 

 which it enters, which bodies subside again when 

 the fire is withdrawn." He further states, in the 

 same page, that " Solids are least expanded by 

 it, inelastic fluids, as water, spirits, &c. &c. 

 more expanded, and elastic fluids, as air, most of 

 all." Knowing this he was led to enquire into 

 the amount of expansion of gases, when sub- 

 jected to the same pressure, and receiving 

 different degrees of heat. This investigation 

 terminated in the establishment of a law, which 

 is, that gases under the same pressure receive 

 equal expansions for equal increments of tem- 

 perature, and always expansions proportional to 

 the temperature. Many similar examples might 

 be given from the history of natural philosophy. 



