140 Obituary Notices of Fellows deceased. 



spontaneity and ease, which made it so' pleasant to listen to. His fame 

 as a speaker began with his earliest lectures to the students of 

 St. Bartholomew's, and it continued to gather force through the whole 

 of his life. The same qualities which distinguished his wva-voce efforts 

 are observable also in his writing. His papers in the Medico- 

 Chirurgical Society's Transactions are models of what such composi- 

 tions should be, not alone in completeness of detail but in clearness of 

 statement. 



J. H. 



HENRY HENNESSY. 18261901. 



Professor Henry Hennessy was the second son of John Hennessy, 

 of Ballyhenessy, and was born March the 19th, 1826, at Cork. He 

 received at school an excellent education in classics, modern 

 languages, and mathematics. His profession was originally that of 

 a civil engineer, but he devoted such time as he could spare from 

 professional employment chiefly to mathematical investigations. 

 His contributions to science number some eighty or more original 

 papers contributed to the " Philosophical Transactions " and " Pro- 

 ceedings " of the Royal Society, to the " Comptes Rendus," and to the 

 Royal Irish Academy. In 1845, in an article published in the 

 " Philosophical Magazine," he proposed to apply photography to the 

 registration of the thermometer and barometer in meteorological 

 observations, and was apparently the first to discern the importance 

 of such records. In 1851 he contributed to the "Philosophical 

 Transactions " his " Researches in Terrestrial Physics," dealing with 

 the figure and primitive formation of the earth and planets, He 

 maintained the view of the fluid origin of these forms, and showed 

 that all the facts concerning the earth which come under our notice 

 are best explained by the existence of fluid matter at a high tempera- 

 ture enclosed within its crust. He wrote on climate (British 

 Association Reports, 1857), and claimed to have proved the existence 

 of laws regulating the distribution of temperature in islands, and to 

 have deduced consequences of general application from the physical 

 properties of water. The gist of his arguments is contained in a paper 

 in the " Proceedings," 1857-59, "On the Influence of the Gulf Stream 

 on the Winters of the British Isles." This led, in 1870, to his being 

 called upon to report on the temperature of waters surrounding the 

 British Isles, for the information of a committee of enquiry into 

 Irish Fisheries. He advocated a great extension of inland river 

 and canal navigation. He also proposed a decimal system of 



