186 REAUMUR. 



manner^ he found out the method of manufacturing 

 tin-plate or whiteiron^ which until then had been 

 brought from Germany. In his various experiments^ 

 he had frequent occasion to observe that melted me- 

 tals assume regular forms on cooling, and he accord- 

 ingly gave an account of the crystallizations which 

 they present. The manufacture of porcelain also 

 engaged his attention^ and received considerable im- 

 provements from him, although he did not succeed 

 in perfecting it. In 1739, he made known a me- 

 thod which he had discovered of giving a whiteness 

 and opacity to glass, which causes it to assume the 

 appearance of chinaware. He was also the first who 

 tried in France the expedient practised by the Egyp- 

 tians for hatching eggs, — a subject which, being of 

 a nature suited to popular apprehension, procured 

 for him at least as much estimation as all his other 

 researches. 



In Great Britain his fame seems to rest almost 

 entirely on his peculiar scheme of graduating the 

 thermometer. He chose the extreme points of the 

 freezing and boiling of water, which, under similar 

 circumstances, are always fixed and unvarying. The 

 interval between these points he divided into eighty 

 degrees, upon the principle that spirit of wine, in a 

 certain state of rectification, expands 80,000 parts. 

 In his experiments on this subject he arrived at 

 some valuable conclusions, in regard to the varieties 

 in their volume and temperature which are exhi- 

 bited by particular fluids when combined, as well as 

 on frigorific mixtures. He also carefully collected 

 the observations on heat made in different places 

 by means of his thermometer. 



The importance and utility of these researches 

 7 



