THOMSON. 125 



system of chemistry, which he published at Edinburgh in the year 

 1804, in four volumes, and afterwards greatly enlarged and im- 

 proved as the demand for the book increased. Dr. Thomson com- 

 menced delivering a series of lectures on chemistry at Edinburgh in 

 1800, which were continued with increasing popularity until 1810. 

 Meanwhile he invented the system of chemical symbols now gene- 

 rally adopted by all men of science (with variations as the time 

 demands), and without which chemical language would be unintel- 

 ligible. He was also the first to open a laboratory in Great Britain 

 for practical manipulation in chemistry. In 1810 he published his 

 ' Elements of Chemistry,' and in 1812 visited Sweden, and on his 

 return wrote a description of that country. The following year to 

 this Dr. Thomson started in London the ' Annals of Philosophy,' a 

 scientific journal, which he continued to edit until the year 1822, 

 and which a few years afterwards was merged in the ' Philosophical 

 Magazine.' He also about this time conducted for the Board of 

 Excise a series of investigations on brewing, which formed the basis 

 of Scottish legislation on that subject. 



In the year 1817 Thomson was elected lecturer on chemistry in 

 the University of Glasgow, and in the following year received the 

 title of Professor. This chair he held until his death, being assisted 

 in his latter years by his nephew and son-in-law, Dr. R. D. Thomson. 

 When Dalton had worked out his grand discovery of the Atomic 

 Theory, he communicated the result of his researches to Thomson, 

 who at once perceived the value and importance of the discovery, 

 and in the year 1807 was the first to publish it to the world. He 

 gave a sketch of this grand theory in the third edition of his 

 ' System of Chemistry ;' and we are chiefly indebted to the labours 

 of Professor Thomson, conjointly with Dr. Henry of Manchester, 

 and Dr. Wollaston, for luminous views on this important subject. 

 In 1825 Dr. Thomson wrote, in two volumes, ' An Attempt to Es- 

 tablish the First Principles of Chemistry by Experiment.' In 1830-31 

 he published his l History of Chemistry,' a work which has been 

 described as a masterpiece of learning and research. In 1836 

 appeared his * Outlines of Mineralogy and Geology ;' and in 1849 

 he issued his last work, ' On Brewing and Distillation.' 



Thomson performed in science, and its history and literature, a 

 very great amount of valuable labour, and acquired a distinguished 

 reputation both as an original discoverer, and as a practical teacher 

 of his favourite science. He died in 1852, at the age of seventy- 

 nine, and has left behind him a son who bears his name, now (1860) 

 superintendent of the East India Company's Botanic Gardens at 

 Calcutta, and one of the most distinguished scientific botanists of 

 the day. Encyclopaedia Britannica, Eighth Edition. English Cyclo- 

 pwdia. London, 1858. 



