xxxvii 



in the perfecting of which he had spent much care and ingenuity. 

 His earliest researches bore on the phenomena of the polarisation of 

 light, upon which he wrote an admirable little handbook, published, in 

 the "Nature Series." At a later period he made a number of com- 

 munications to the " Proceedings of the Royal Society " on the 

 electric discharge in rarefied gases. In 1879 he was joined in his 

 researches on this subject by Mr. J. F. Moulton, and in conjunction 

 with him entered upon an investigation of the sensitive state of the 

 discharge. An important paper in the " Philosophical Transactions " 

 of 1879 (pp. 165 — 229), and some shorter notes subsequently pub- 

 lished in the Society's "Proceedings," give in detail the singular and 

 elegant results which were arrived at. 



The great beauty of the experiments involved in Mr. Spottiswoode's 

 physical researches led to demands from his friends that they should 

 be laid before the public in a popular form. The lectures which he 

 delivered to crowded audiences at the Royal Institution and elsewhere 

 were characterised by a remarkable clearness of exposition, and by a 

 depth of poetic feeling which excited much surprise among those who 

 knew of him only as an abstruse mathematician. Perhaps the most 

 interesting example of his powers as a lecturer is to be found in a 

 discourse on " Sunlight, Sea, and Sky," delivered to working men at 

 the British Association Meeting in Brighton in 1872 ("Nature," 

 vol. vi, pp. 333 — 336). The reputation he acquired in these essays 

 excited high expectations with regard to the address which, as 

 President of the British Association, he had to deliver in Dublin in 

 1878. These expectations were fully justified by the result. The 

 stores of a mind imbued with the spirit of a philosopher, a mathe- 

 matician, a physicist, and a poet, were drawn upon with no niggard 

 hand, and matters usually regarded as beyond the ken of others than 

 experts were explained to the unversed in language as interesting as 

 it was simple, clear, and precise. The judgment of his fellow- workers 

 could now be unhesitatingly approved by others. 



The honours which were bestowed on Mr. Spottiswoode were 

 many. He was LL.D. of Cambridge, Dublin, and Edinburgh, and 

 D.C.L. of Oxford. He was elected correspondent of the Institute 

 (Academie des Sciences) for the Geometrical Section, after a sharp 

 contest with M. Borchardt. He was Fellow of the Royal Society of 

 Edinburgh, the Royal Astronomical Society, the Royal Asiatic 

 Society, the Royal Geographical Society, the Society of Antiquaries, 

 and the Ethnological Society. He occupied the Presidential Chair of 

 Section A of the British Association in 1865, of the London Mathe- 

 matical Society in 1870-2, of the British Association in 1878, of which 

 latter body he acted as Treasurer from 1861 to 1874. Of the Royal 

 Institution he was Treasurer from 1865 to 1873, and Secretary from 

 1871 up to his death. He was also a Trustee of the British Museum. 



