548 



r> I- A C K. 



Ulack. survived him, who afterwards claimed the kingdom 

 {"or her son. But the Romans rejected her claim, 

 and retained it as a province, till it was wrested from 

 by the Turks, to whom it still belongs, (x) 



BITS. See Brides. 



BL.AC K, Dr Joseph, was born in France, on the 

 banks of the Garonne, in the year 1728. His father, 

 Mr John Black, was a native of Belfast in Ireland, 

 but of a Scots family, which had been for some time 

 settled in that country. Mr Black re'sided for the 

 most part at Bordeaux, where he carried on the wine 

 trade. He married a daughter of Mr Robert Gordon, 

 of the family of Hillhead in Aberdeenshire, who was 

 also engaged in the same trade at Bordeaux. In the 

 year 1710, when young Black had reached the age 

 of 12, he was sent home to Belfast, that he might 

 have the education of a British subject. After the 

 ordinary instruction of a grammar school, he was sent 

 in 1746 to continue his education in the university of 

 Glasgow. Being required by his father to make choice 

 of a profession, he pitched upon medicine, as most 

 suited to his peculiar views, and congenial to his studies. 

 Fortunately at this period Dr Culleji began his 

 great career, and had pitched upon philosophical che- 

 mistry as a field hitherto untraversed and unopened. 

 It had been treated as a curious art, susceptible of 

 improvement from rational inquiry and discussion. 

 But Dr Cullen saw in it a great department of the 

 science of nature, founded on principles as immutable 

 as those of mechanical philosophy. He undertook 

 the task of developing and arranging these principles, 

 and he promised to himself great reputation from the 

 accomplishment of it. His pupils, in consequence of 

 his new views, became zealous chemists, and young 

 Black in particular devoted himself to the study. 

 This was soon observed by Dr Cullen, who possessed 

 the happy talent of exciting and encouraging his pu- 

 pils in an eminent degree. Mr Black became his in- 

 timate friend, his assistant in all his investigations, and 

 his experiments were frequently quoted in the lecture 

 as sufficient proofs of the positions of the professor. 



In 1750 he went to Edinburgh to finish his medi- 

 cal studies, and he lived in the house of Mr James 

 Russel, professor of natural philosophy, his cousin- 

 german. About this time the professors had adopted 

 different opinions respecting the action of lithontrip- 

 tic medicines. Those which produced the most power- 

 ful effects in alleviating the sxcruciating pains of the 

 stone, were of a very corrosive nature. It was there- 

 fore an object of great importance, to discover, if pos- 

 sible, some equally efficacious medicine, which shall 

 not possess corrosive properties ; or if that cannot be 

 done, at least to diminish or destroy the corrosiveness 

 of the medicines in use, without impairing their me- 

 -dical virtues. It was the6e views that led Mr Black 

 to investigate the nature and properties of magnesia, 

 and which induced him to contrive and execute the 

 experiments which laid open the nature of causticity 

 itself, and showed upon what it depends. This im- 

 portant subject he destined for his inaugural disserta- 

 tion ; and he appears to have delayed taking out his 

 medical degree till he had brought his investigation 

 to a state of maturity. 



Fortunately when he took his doctor's degree, and 

 published his important discovery of-the cause of the 



difference between limtstone and quicklime, mild a 

 caustic alkalies, a vacancy occurred in the choir, 

 chair in Glasgow. His friend and master Dr Cullen 

 having been removed to Edinburgh, there could be 

 no hesitation in bestowing the vacant chemical chair 

 upon the author of a discovery, which was destined to 

 produce a complete revolution in chemical science. 

 Dr Black was accordingly appointed professor of ana- 

 tomy and lecturer on chemistry in the university of 

 Glasgow in the year 1756'. Not considering himself 

 as well qualified for the professorship of anatomy, he 

 exchanged tasks with the professor of medicine, with 

 the concurrence of the university. 



While in Glasgow, therefore, his lectures on the 

 institutes of medicine constituted his chief task. T 

 gave general satisfaction, by their clearness and si 

 plicity, and by the cautious moderation of his gi 

 ral principles. He became likewise a favourite prac- 

 titioner in that rich and active city, arid his business 

 extended every year during his whole stay in Glas- 

 gow. Thus th? greatest part of his time vv.as taken 

 up in the practice of medicine, or in increasing his 

 stock of medical knowledge with a view to the im- 

 provement of his lectures. Chemistry, as far at least 

 as he was professionally concerned, constituted but a 

 secoudary object. This may serve, in some measure 

 at least, to explain the seemingly unaccountable fact, 

 that he never attempted to enter that vast and tempt- 

 ing field of investigation which he had laid open. 



It was during this period, however, that he inves- 

 tigated and brought to maturity another discovery of 

 the utmost importance, we mean his theory of latent 

 heat ; a discovery which constitutes the foundation of 

 the whole doctrine of heat as at present taught by 

 chemists, and which has been attended with more be- 

 neficial effects to the world than any other discovery 

 made during the 18th century; since it occasioned 

 the improvements in the steam engine by Mr Watt, 

 an instrument which has operated a complete change 

 in our manufactures. The decisive experiment was 

 made in 1761, and Dr Black drew up an account of 

 this theory, and read it to a literary society in Glas- 

 gow on the 23d April 1762. No account of this 

 theory was ever published by its author ; but ever 

 after it made a most important part of his chemical 

 lectures. It became in consequence soon generally 

 known in every part of Europe. 



About this time likewise he made a set of experi- 

 ments, to determine whether the expansions of the 

 thermometer corresponded correctly with the increase 

 of heat. He satisfied himself that they did^ so, and 

 that the thermometer measured the increase of tem- 

 perature correctly. The result of his experiments 

 was read to the literary society of Glasgow on the 

 28th March 1760. 



In the year 1766, Dr Cullen, chemical professor in 

 Edinburgh, was appointed professor of medicine, and 

 Dr Black, with the unanimous approbation of the city 

 and university, was pitched upon as his successor. In this 

 new scene, his talents were moreconspicuous,'and more 

 extensively useful. The celebrity of the medical school 

 of Edinburgh brought him pupils from all quarters, 

 while the increasing importance of chemistry, both 

 in the eye of the philosopher and manufacturer, made 

 the number of chemical students increase every year. 





