ON THE HISTORY OF TERRESTRIAL PHYSICS. 585 



have not yet been superseded by the latest publications. Our country- 

 men, Ray and Willughby, contributed also to add much new matter to 

 the stores of natural history, in all its departments ; and their labours, 

 as well as those of Tournefort and Re'aumur, are of the more value, as they 

 were far more studious than their predecessors to discriminate truth from 

 fiction. 



The foundation of the most celebrated of the philosophical societies of 

 Europe renders the latter half of the seventeenth century a very interesting 

 period in the history of natural knowledge. The Royal Society of London, 

 and the Academy of Sciences of Paris, have always been the most distin- 

 guished of these : and the Florentine Academy del Cimento, although its 

 labours were not of long duration, produced at first in a short time 

 a very copious and interesting collection of experiments, relating to various 

 subjects of physical research. In the Royal Society, Boyle, Hooke, and 

 Newton were the most industrious, as well as the most successful inves- 

 tigators of natural phenomena : the elementary doctrines of chemistry, the 

 nature of combustion, the effects of heat and cold, and the laws of attrac- 

 tion, repulsion, and cohesion were attentively examined and discussed. 

 The expansion of water, by a reduction of its temperature, near the freez- 

 ing point, was first observed by Dr. Croune ; although his experiments 

 were considered by Dr. Hooke as inconclusive.* The attention of the 

 society was directed by Newton to the phenomena of electricity, some of 

 which had been a short time before particularly noticed by Guericke ; the 

 mode of making electrical experiments was greatly improved by Hauks- 

 bee ; this accurate observer investigated also the nature of capillary attrac- 

 tion with considerable success. Early in the succeeding century, many of 

 the members of the Academy of Petersburg followed the example of other 

 societies with great industry ; and the experiments of Richmann on heat 

 were among the first and best fruits of their researches. 



Dr. Halley employed himself, with the most laudable zeal, in procuring 

 information respecting the variation of the compass ; he undertook a 

 voyage round the world, for the express purpose of making magnetical 

 observations ; and he published a chart of variation, adapted to the year 

 I700.f He also collected many particulars respecting the trade winds and 

 monsoons, and he endeavoured to explain them by a theory which has 

 been adopted by some of the latest authors, but which is in reality much 

 less satisfactory than the hypothesis proposed some time afterwards by 

 Hadley.^ His magnetical investigations were continued with great dili- 

 gence by Montaigne and Dodson, who published, at different periods, two 

 charts representing the successive states of the variation. Euler, Mayer, || 

 and others have attempted, in later times, to discover such general laws as 

 might be sufficient to determine the magnitude of the variation for every 

 part of the globe ; but their success has been very much limited. 



The science of electricity was diligently cultivated in the middle of the 

 last century by Stephen Gray, Dufay, Winkler, Nollet, Musschenbroek, 



* Birch, iv. 26, 253. f Ph.Tr.xxiii. 1106. J See p. 681. 



Hist, et Mm. de Berlin, 1755, p. 107 ; 1757, p. 175 ; 1766, p. 213. 

 II Gott. Anz. 1760, p. 633 ; 1762, p. 377. 



