SULPHUR PHOSPHORUS CARBON. 95 



when heated in air, and its more intense combustion in oxygen 

 gas being exhibited ; and the interesting fact stated and com- 

 mented upon, that oxygen gas, in this process, unites with its 

 own weight of sulphur without increasing in bulk; its specific 

 gravity being of course doubled, in thus becoming sulphurous 

 acid. The other compounds of sulphur with oxygen were briefly 

 described, and sulphuric acid, as consisting of one of them, in 

 union with water, exhibited, together with some saline com- 

 binations of the same body, as Epsom salts, (sulphate of mag- 

 nesia, with water,) Heavy Spar, (sulphate of barytes,) Gyp- 

 sum, (sulphate of lime, with water,) Plaster of Paris, (mere 

 sulphate of lime, being gypsum from which the water has 

 been expelled,) &c. 



The successive, though original, but not independent dis- 

 covery of PHOSPHORUS, by Brandt of Hamburgh, Kunckel 

 of Dresden, and our own celebrated countryman the Hon. 

 Robert Boyle, was related, in introducing that substance as 

 another of the simple combustibles, and the method of ex- 

 tracting it from bones was explained. Its Physical and Che- 

 mical properties were exhibited, and the pupils strongly cau- 

 tioned against its careless use, on account of the extreme 

 readiness with which it enters into combustion, the difficulty 

 of extinguishing it when once inflamed, and the painful burns 

 it inflicts when in that state. The combinations of phos- 

 phorus with the supporters of combustion, oxygen, chlorine, 

 and iodine, were mentioned ; and the preparation of phos- 

 phuretted hydrogen gas, which inflames, spontaneously, on 

 coming into contact with oxygen, either pure, or as contained 

 in atmospheric air, concluded the subject. 



A portion of the history of CARBON having been given be- 

 fore, when investigating the contamination of atmospheric 

 air by carbonic acid gas, during respiration, the remainder 

 of that subject was now entered into; the various mineral forms 

 of Carbon, as the Diamond, Graphite (improperly called black- 

 lead), and Anthracite or Stone- Coal (Welsh Culm &c.), being 

 described, and specimens of them exhibited. Carbon was 

 stated to be the basis of the structure of all the beings belong- 

 ing to the Vegetable Kingdom ; and in connection with this 

 statement, the various kinds of charcoal were considered, and 

 those of vegetable carbon, (combined, however, with other ele- 

 ments,) altered by long-continued burial in the earth, as Lig- 

 nite or Bituminous Wood, and Jet, also the Mineral Resins 

 and the Bitumens, leading to Common Coal. Its existence in 

 Animal-matter was noticed ; and the history of one of its com- 

 pounds with oxygen, carbonic acid, having already been de- 

 tailed, the subject, as well as this Course of Lectures, was 



