July 25, 1901] 



NA TURE 



507 



subject of the Shorter Catechism. It was, therefore, no 

 surprise to some when he and Balfour Stewart proved to 

 be joint authors of " The Unseen Universe " (first printed 

 privately in 1875''. This remarkable book reflects the 

 extraordinary width of Tait's knowledge and of his in- 

 terest in things known and unknown : its success, so far 

 as its immediate object was concerned, is best described 

 by Tait himself in an obituary notice of Balfour Stewart. 



" It has passed through many editions, and has ex- 

 perienced every variety of reception — from hearty welcome 

 and approval in some quarters to the extremes of fierce 

 denunciation, or of lofly scorn, in others. Whatever its 

 merits or demerits, it has undoubtedly been successful in 

 one of its main objects, viz. in showing how baseless is 

 the common statement that ' Science is incompatible with 

 Religion.' It calls attention to the simple fact, ignored by 

 too many professed instructors of the public, that human 

 science has its limits, and that there are realities with 

 which it is altogether incompetent to deal." 



Tait's scientific memoirs are being republished in three 

 goodly volumes by the Pitt Press, two of which have 

 already appeared. It is therefore unnecessary to do 

 more than allude to the most important of them. The 

 subjects range over pure and applied mathematics and 

 experimental physics. The majority of the mathematical 

 papers are written in the quaternion notation, and 

 this has undoubtedly prevented some of them from 

 becoming so well known as they deserve to be. We 

 may mention specially two papers on Fresnel's wave 

 surface (1859) ; a series of papers on the properties of 

 " nabla '' (v), and on the linear and vector function, extend- 

 ing from 1867 to 1900 ; on the rotation of a rigid body 

 about a fixed point (1S6S) — a paper of great power and 

 elegance, which exhibits Tait's mathematical power at 

 its best; on Green's and other allied theorems (1870), 

 on orthogonal isothermal surfaces (1S72) ; on knots (1877, 

 1SS4, 1885), a series of three papers suggested by the 

 problem of the possible configurations of a Thomson 

 vortex atom. In the three classical papers last named 

 he virtually creates a new chapter in the geometria 

 situs, and is brought into relation with the work of 

 Listing, for whom he had the greatest respect. To this 

 subject he returns again in two subsequent papers : a 

 note on a theorem in geometry of position (1S80), and on 

 Listing's topologie (1884). 



His first experimental work was on ozone, in collabor- 

 ation with .\ndrews (from 1856 to i860). He also began 

 to work with the same distinguished investigator on the 

 compression of gases, but this was interrupted by his 

 removal to Edinburgh in i860. His memoir on thermal 

 and electric conductivity contains the result of an 

 elaborate series of experiments extending over ten years. 

 The original idea of the method was due to Forbes, but 

 the complete theory and the difficult details are the work 

 of Tait and his pupils. The memoir on mirage is a re- 

 markably elegant and effective combination of experi- 

 mental and mathematical methods, and is, perhaps, the 

 best example of Tait's work as a natural philosopher. 

 His investigation of the pressure errors of the Challenger 

 thermometers was an intricate piece of experimental 

 work extending over several years. It led him into the 

 discussion of the compressibility of liquids, to which are 

 devoted five memoirs (1893-1898). This investigation 

 brought him into close relations with the French physicist 

 Amagat, for whom he had a great regard. Much work is 

 embodied in five papers (1886-1892) on the founda- 

 tions of the kinetic theory of gases, in which he 

 endeavours to analyse into their logically simplest ele- 

 ments the first principles of a difficult and much-debated 

 subject. His interest in the game of golf produced three 

 important papers on impact (1888-1892), and two on 

 the path of a rotating spherical projectile. On this 

 subject he also wrote a series of popular articles which 

 were widely read and appreciated. 



NO. 1656, VOL. 64] 



Besides his text-books and original memoirs, Tait 

 contributed assiduously to the current scientific literature 

 of his day. We may mention in particular his article 

 "On Energy" in Good Words (1863); his memoirs of 

 Hamilton {North BritisJi Review, 1866) and of Andrews 

 (along with Crum Brown, 1888) ; his famous lecture " Or> 

 Force " (British Association, 1876), so cleverly parodied 

 in Maxwell's poem — 



'■ Ve British asses who expect to hear 

 Ever some new thing, &c." ; 



his article " On the Teaching of Natural Philosophy ' 

 {Contemporary Review, 1S78) ; his fine appreciation of 

 Maxwell's scientific work (N.^iX^RE, vol. xxi. p. 317, 

 February 5, 1880), and his various contributions to the 

 ninth edition of the " Encyclopedia Britannica.'' 



Limitations of time and space, and others besides, make 

 it impossible to attempt here any appreciation of the rela- 

 tive importance of Tait's original contributions to the 

 science of the \'ictorian age. For one thing, the sense of 

 bereavement is too near to us to permit of the necessary 

 historical abstraction. Nor is this the time to enlarge 

 on the polemical discussions in which Tait took part. 

 Ready to take a blow, he did not always spare his 

 strength in giving one, and his opponents did not 

 always relish his rough play. It may be doubted 

 whether many of them carried for long any resulting 

 bitterness ; but undoubtedly some of them were led, 

 temporarily at least, greatly to mistake his character. 

 Personal contact with him at once dissipated any such 

 misconception. To feel the magic of his personality to 

 the full it was necessary to visit him in the little room at 

 the back of his house. No. 38 George Square, Edinburgh, 

 the Spartan simplicity of whose plain deal furniture and 

 book-shelves, unpainted, unvarnished, ink-spotted, littered 

 with books and pamphlets and with piles of manuscript 

 bristling with quaternion symbols, was so finely in tune 

 with the tall, rugged figure, the loud, hearty greeting and 

 the radiant, welcoming smile of the kindly host. Ter> 

 minutes in that sanctum would have made a friend of his 

 bitterest foe, and the conquest would have been mutual 

 and permanent, for it seemed to be an axiom of Tait's that a 

 man who had become his friend could sin no more. Thither 

 came at various times Joule, Andrews, Kelvin, Stokes,, 

 V. Helmholtz, Rankine, Clerk-Maxwell, Balfour Stewart, 

 Rowland, the Wiedemanns (father and son), Adams, 

 Newcomb, Huggins, Newton, Lockyer, Hamilton (at 

 least in the spirit), Cayley, Sylvester, Ilermite, Cremona, 

 Clift'ord, Klein, Bierens de Haan and many more, the 

 majority, alas ! now departed like their common friend. 

 It has been the main part of our endeavour to indicate, 

 faintly at least, some of the qualities that attracted 

 and retained such a galaxy of friends ; the most potent of 

 all was doubtless the oldest, the simplest ground of liking 

 — he was loved so well because he loved so much. 



G. Chrvst.\l. 



NOTES. 



The Hughes Bennett laboratory of experimental physiology, 

 which has been added to the University of Edinburgh by Mrs. 

 Cox as a memorial of the work of her father. Prof. J. Hughes 

 Bennett, in connection with medical education, was formally 

 handed over to the University on Saturday last. The addition 

 comprises a large laboratory equipped with appliances for prac- 

 tical work in experimental physiology by individual students, 

 and a small lecture theatre for class demonstrations. The 

 memorial character of the new laboratory is indicated by a bronze 

 has relief representing Hughes Bennett, which has been 

 executed by Mr. MacGillivray. This is fixed to one of the 

 walls of the laboratory, with an inscription beloiv it commemor- 

 ating the fact that Hughes Bennett was the first teacher in 



