Hijloty of Ajlronomy for the Year i8o2. 209 



*^,* Mr. Portal is probably not aware that the theory 

 which he attributes to Dr. Thomfon as its author was firft 

 piropofed by Dr. Gren, whofe doftrine is briefly as follows: 



Oxygen gas is compofed oi oxygen and caloric — CsmbujIibU 

 bodies confilt of their refpe£live ba/ls in chemical combination 

 with the matter of light — Free light confifts of the matter of 

 light united to caloric. 



Combuftion, then, is a mere play of chemical affinities; 

 the oxygen of the oxygen s:as uniting with the bdfe of the 

 inflammable bodv to form an oxide or an acid, while the 

 caloric of the gas unites with the matter of light of the com- 

 bufl;ible body, and forms free or vifible light. By this theory, 

 no combuftible fubftance can be a fimple body — by Lavoi- 

 lier's, they may. — See Gren's Principles of Modern Chemijiry^ 

 Englifli edition, chap. ii. articles Caloric, Light, Phlogijlon, 

 Combiijlion. — A. T. 



XXXVII, Hijlory of Ajlronomy for the Year \^02. Read in 

 the AthencEum of Paris December 30, hy Jerome La- 



LANDE. 



[Concluded from p. 179.3 



V>/N the 7th of June I publidied the two lad volumes of 

 the large Hiftory of the Mathematics by Montucla. The 

 fourth is almoft entirely deyoted to the hiftory of aftronomy 

 and navigation, which I communicated to the prefent period. 



There has appeared alfo, in two volumes quarto, with 23 

 plates, Hi/loire de la Mefure du Temfs far lei Horloges, by 

 Ferdinand Bcrthoud, mechanift of the marine, member of 

 the National Inftitute, and of the Royal Society of London. 

 It contains a dcfcription of efcapements, compenfation ba- 

 lances, moving fpheres, and of the principal inventions of 

 clock-work. The author fpeaks of all the celebrated clock- 

 makers, except Louis Berthoud, his nephew, to whom we are 

 indebted for all the time-keepers made fince 1784. I fliall 

 here take occafion to obferve, that Mr. Emery died at Lon- 

 don, and that his widow has four lime-keei)ers which (he 

 wiflies to difpofc of: they would be a valuable acquifition. 



We have received the 7th volume of the Tranfadlions of 

 the Royal Iriih Academy, publiflicd in 1800, and in which 

 Mr. Young examines the folution given by Newton of the 

 problem relpcfting prectflion of the ecpiinoxes; alfo the 8th 

 volume of the Irifh Tranfacitions, Dublin 1802. 



Ch\ the i8thof July my fmall tables of logarithms ap- 

 peared : they are the moft convenient and the mott correft 

 ytt given. 



Vol. XV. No., 59. P The 



