365 Intelligence and Mifcellaneous Articles. 



vault of the furnaces of the Devon iron-works; together with 

 fome pra6lical remarks on the management of biaft-furnaces. 

 By Mr. Roebuck. (See the prefcnt number of the Philofo- 

 phical Magazine, p. 334.) 



III. Experiments on whinftone and lava. By Sir James 

 Hall, Bart. 



IV. A chemical analyfis of three fpecics of whinftone 

 and two of lava. By Dr. Robert Kennedy. 



V. A new method of refolving cubic equations. By James 

 Ivory, Efq. 



INTELLIGENCE, 



MISCELLANEOUS ARTICLES. 



JL EAR NED SOCIETIES. 



ROYAL SOCIETY OF LONDON. 



OiNCE our laft report, feveral interefting papers by 

 Dr. Herfchel, on the fubjeft of his late difcovery refpe6t- 

 ing heat and light, have been read. Doftor Herfchel, pur- 

 fuing his late difcovery of what he calls the invifible heat- 

 making rays of the fun, has inveftigated, and experimentally 

 proved, that heat is occafioned by rays emanating from can- 

 dent fubftances ; and that thefe rays have a power of heating 

 bodies, and are fubjeil to the laws of refleftion and of refrac- 

 tion. The Do6lor divides heat into fix claffes ; three of 

 which are folar, and three tcrreftrial. On account of the 

 fimilarity between the former and the latter, he reduces his 

 fubje6t to three general heads. He treats in his fird divifion 

 of the heat of the fun and of terreflirial flame ; in the feco^d, 

 of the heat of prifmatic rays and of red-hot iron; and inth^ 

 third divifion, of the invifible heat-making rays of the fun, 

 and of terreftrial invifible or dark heat in general. 



7 Papers 



