426 MEMOIR OF THE LATE DR THOMAS CHARLES HOPE. 



contended could not have happened, if liquids had been absolute non-conductors 

 of caloric. 



These experiments seem sufficiently conclusive ; but Count Rumford still 

 insisted, that the rise of the thermometer was only owing to the conduction by 

 the sides of the containing vessel, in Hope's experiments, as well as in the 

 analogous investigations of Thomson, Nicholson, and Dalton. 



This objection suggested to the late Dr John Murray the ingenious idea of 

 employing a hollow cylinder of ice as the containing vessel ; which, as its tem- 

 perature could not rise above 32°, could not conduct or communicate any heat to 

 the thermometer. Water could not be employed in this apparatus, on account 

 of its anomaly in expanding by cold near its freezing point; but olive-oil, 

 cooled to 32°, Avas used ; and in experiments made by suspending the heating 

 cause in contact with the surface of the oil, the thermometer rose, in a longer or 

 shorter intei-val, in proportion to the greater or less depth of the instrument beloAV 

 the surface of the oil.- — ( Nicholson'' s Journal, 8wo series, I. 425. J 



In considering these experiments and the objections stated, it occurred to 

 me, that if the same apparatus were employed with different fluids, did the rise 

 of the thermometer depend on the conduction of the sides of the vessel, that rise 

 should be nearly equal, whichever liquid was employed. I tried this with ten 

 difierent liquids; and though the apparatus was the same, and the distance 

 between the source of heat and the thermometer similar, yet the time required to 

 raise the thermometer to the same point, was very different with the different 

 liquids : this I ascribed to the difference in the conducting power of each liquid. — 

 (Nicholsons Journal, XII. 137, for 1805. j 



All these investigations confu-med the view taken by Hope, that though 

 liquids were very slow conductors of caloric, they could not be considered, as was 

 alleged by Rumford, absolute non-conductors. 



Dr Hope's reputation as a teacher of chemistry, arising from the causes 

 already noticed, and his tact in exciting in his hearers his own enthusiasm for 

 the study, long continued to attract vast crowds of pupils. His honours kept 

 pace with his reputation. 



In 1810 he was elected a Fellow of the Royal Society of London ; in 1815 he 

 was chosen President of the Royal College of Physicians of Edinburgh, an office 

 which he continued to fill for four successive years ; in 1820 he was admitted an 

 honorary member of the Royal Irish Academy ; and in 1823 he became one of the 

 Vice-Presidents of this Society, an office which he held until his death. During his 

 connection with the College of Physicians, he took an activfe part in the prepara- 

 tion of the ninth and tenth editions of theu' Pharmacopoeia, especially in that 

 published in 1817. For several years, besides his duties as a Professor of Che- 

 mistry, Dr Hope gave an annual com-se of Clinical Medicine in this University, 

 which was also numerously attended. But for many years .before his death, he 



