VI 



In this year he was appointed Professor of Civil Engineering 

 and Surveying in Queen's College, Belfast. He became fully occu- 

 pied with the duties of his professorship, and gave up his office and 

 business as a civil engineer, except for the connection which he re- 

 tained with some of his former clients, and for business in consulta- 

 tion. 



The professorship in Belfast he held till the death of Macquorn 

 Rankine in 1872. By this event the Professorship of Civil Engineering 

 in Glasgow became vacant; and James Thomson was in the next 

 year appointed by the Government to succeed him. 



In ] 888 his sight unfortunately began to fail ; and the malady, 

 from which both his eyes suffered, proceeded so far that it became 

 necessary for him to resign his University work. This he did after the 

 end of the session 1888-89. Happily, however, he retained more or 

 less of his eyesight till the end of his life ; and as he became more 

 accustomed to the condition of his eyes he was better able to make use 

 of what remained to him, and was able to move about freely with but 

 little assistance, and even to read and write a little, and to make on 

 a large scale the diagrams which he used to illustrate his Bakerian 

 Lecture on " The Grand Currents of Atmospheric Circulation." 



His death was almost sudden and was the beginning of a sadly 

 tragic time in his family. In a single week Professor Thomson, his 

 wife, and youngest daughter were all attacked with cold, which was 

 quickly followed by inflammation of the lungs. The next week saw 

 the death of all three ; his daughter surviving him only three days, 

 and Mrs. Thomson seven days. Professor Thomson's death took 

 place on the 8fch of May, 1892. 



It is not possible in the limits to which this notice must be confined 

 to refer to all James Thomson's papers, nor to give a complete list of 

 the many subjects which occupied his attention. 



Already some of his contributions to thermodynamics have been 

 mentioned ; but it must be further remarked that during the portion 

 of his life which was occupied with teaching, he gave great attention 

 to this subject, endeavouring to improve the nomenclature and modes 

 of expression of the various principles and propositions connected 

 with it, and to simplify modes of explanation and of statement. 



Another very remarkable contribution to thermal science and 

 thermodynamics was his extension of Andrews' discoveries on the 

 subject of the continuity of the liquid and gaseous states of matter. 

 Thomson's mode of conception of the whole subject, which led to the 

 construction of a model in three dimensions to show the mutual rela- 

 tions between pressure, volume, and temperature of such a substance 

 as carbon dioxide under continuous changes of pressure, and volume, 

 and temperature, was perfectly new and most important. The model 

 itself threw a flood of light on the question and the imagining of the 



