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OBITUARY NOTICE OF FELLOW DECEASED. 



James Apjohn, M.D., was Professor of Chemistry in the University 

 of Dublin from 1850 to 1875. He died on the 2nd of June, 1886, at 

 Southill, Blackrock, co. Dublin, in his 91st year. Dr. Apjohn was 

 born at Sunville, co. Limerick, on the 1st of September, 1796, and, 

 having received his elementary education at the Tipperary Grammar 

 School, he entered Dublin University in 1814. After a distinguished 

 undergraduate course, he took his Arts degree in 1817, and in 1821 

 obtained the M.B. Sixteen years later he proceeded to the M.D. 

 degree. Apjohn's love for experimental science seems to have been 

 kindled during his medical studies, and after graduating he devoted 

 himself almost exclusively to the pursuit of chemistry and physics. 

 About 1824 several eminent physicians and surgeons — including 

 Groves, Marsh, Jacob, and Cusack — decided to establish a new 

 medical school at Parke Street, in Dublin, and in the following 

 year Apjohn joined the staff of the new school as lecturer in 

 chemistry. Here he acquired considerable reputation as a lecturer, 

 and three years later he was transferred to the newly-established 

 Chair of Chemistry in the College of Surgeons' School, which he held 

 until 1850, when he was appointed to the University Chair of Che- 

 mistry on the death of Dr. Francis Barker. Apjohn's official con- 

 nexion with the University began, however, in 1841. About that 

 time the Board of Trinity College founded an Engineering School, 

 and appointed Apjohn to the Chair of Applied Chemistry and 

 Mineralogy — an office which he continued to hold when he succeeded 

 Barker in 1850. On Dr. Apjohn's retirement from professorial work, 

 Mineralogy was transferred to the Chair of Geology in the University, 

 and Applied Chemistry was permanently attached to the Chair of 

 Chemistry. 



The principal scientific work of Dr. Apjohn was rather physical 

 than chemical. The general study of hygrometry had a special 

 attraction for him, and of the forty-nine scientific papers named in the 

 Royal Society's Catalogue, a large proportion relates to that subject. 

 In the course of his work on the theory of the wet bulb hygrometer, 

 he arrived at the expression well known as " Apjohn's Formula" for 

 ascertaining the dew point. 



The study of hygrometry led to much interesting work on the 

 specific heat of gases, and in 1837 Apjohn received the Cunningham 

 Medal from the Irish Academy for his paper " Upon a New Method 

 of Investigating the Specific Heats of the Gases." The method con- 

 sisted in noting the fall in temperature suffered by the wet bulb 

 thermometer when immersed in the perfectly dry gas, whose specific 



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