380 Obituary Notices of Fellows deceased. 



'On the Philosophy of Teaching or Psychology ' before the Literary 

 and Philosophical Society of the University of Glasgow, in 1858, until 

 he died, he published a great number of investigations, the titles of 

 thirty-three of them (previous to 1883) being given in the Eoyal 

 Society's Catalogue. Most of these were published in the "Philo- 

 sophical Magazine" or the reports of the British Association. The 

 reduction of observations of deep-sunk thermometers will be found in 

 "Philosophical Transactions," 1860. The results of his experiments 

 on torsion and flexure were published in three papers, " Philosophical 

 Transactions," 1866-7-8. ' Observations of Atmospheric Electricity at 

 Kew and Nova Scotia ' was published in " Philosophical Transactions," 

 1867. Three of the papers are in " Transactions," Eoyal Society, 

 Edinburgh, and five in the " Proceedings," Eoyal Society, London. In 

 1866 he published a new Proportion Table consisting of two cardboard 

 sheets, forming what is equivalent to a very long slide rule. After 

 1883 he published about as many papers as are mentioned in the 

 Catalogue. A paper on * Geometrical Illustrations of the Theory of 

 Eent' appeared in the Eoyal Statistical Society's "Journal" in 1900. 

 Some investigations of the algebra of difference tables in the " Quarterly 

 Journal of Mathematics " were followed by the discovery of a new and 

 very useful interpolation formula, an account of which was published 

 by request of the Institute of Actuaries in their Journal. He took 

 much interest in the Meetings of the Physical Society, of which he 

 was Vice-President, and many of his later papers were read there. 

 During his last days he was engaged in correcting the proofs of the 

 evidence he had given before the Eoyal Commission on Coal Supplies, 

 mainly dealing with questions of underground temperature. 



From 1868 until he died he made few experimental investigations, 

 but he published many papers in which he helped to elucidate and 

 draw conclusions from the results obtained experimentally by others. 

 He invented or simplified methods of calculation. He made no great 

 discovery, but his work did much to connect and make clear the great 

 discoveries of his time. 



J. P. 



