THE ASTRONOMICAL VIEW OF NATURE. 331 



the great reciprocal influence which science has gained in 

 the course of this century over practical life, I am still 

 doubtful whether scientific thought has, at the end of 

 our century, as yet balanced the debt which it owes to 

 practical inventors. It is instructive, for instance, to 

 consider how much, in the hands of Eumford, of Sadi 

 Carnot, of Hirn, and of Eankine, science has learnt from 

 the steam-engine, and to reflect whether from all the 

 theoretical insight gained any really radical improve- 

 ment of the steam-engine still one of the most imperfect 

 machines has resulted.-^ 



Lord Kelvin ; and it has in an- 

 other direction led to remarkable 

 scientific results in the hands of 

 Gauss, who Vjetween the years 1830 

 and 1840 brought the theory al- 

 most to perfection. Here again 

 the physical phenomenon required 

 for its treatment a special mathe- 

 matical analysis, which Gauss gi-eat- 

 ly furthered in his ' Allgemeiue 

 Lehrsiitze in Beziehung auf die im 

 verkehrten Verhaltnisse des Quad- 

 rats der Entfernung wirkenden 

 Anziehungs - und Abstossungs- 

 Knifte ' (1840). This is a matiiema- 

 tical investigation of the Newtonian 

 gravitation-formula. Gauss followed 

 out the theories of Laplace and La- 

 grange simultaneously with Green, 

 whose now celebrated memoir on 

 the subject remained long unknown 

 (see supra, pp. 231, 247). The mathe- 

 matical theory showed that in a 

 sphere containing a certain amount 

 of attracting (magnetic) matter an 

 ideal distribution on the surface of 

 the sphere can be found which 

 takes the place of the real but un- 

 known distribution in the interior, 

 and that if through observation the 

 necessary data are supplied, the 

 magnetic condition of anj' point 

 on the surface can be foretold with 

 great approximation. As an ex- 



ample, Gauss foretold from the 

 imperfect data at his command 

 the position of the south magnetic 

 pole. In 1840 Capt. Sir James Ross 

 approached it sufficiently to show 

 the correctness of the calculation. 

 The theoretical investigations in 

 connection with magnetic attrac- 

 tion and with tidal movements 

 have remodelled the methods of 

 observation of the phenomena them- 

 selves, the older methods having 

 proved to be in many ways insuf- 

 ficient. A full account of Gauss's 

 labours here referred to will be 

 found in E. Schering, ' C. F. Gauss 

 und die Erforschung des Erdmag- 

 netismus,' Gottingen, 1887. 



^ I refer in this matter to two 

 addresses delivered recently one 

 by Prof. Unwin ('Electrician,' voL 

 35, pp. 50 and 79) on "The De- 

 velopment of the Experimental 

 Study of Heat - Engines " ; the 

 other by Prof. Lodge on "The 

 Second Law of Thermodynamics " 

 ('Electrician,' vol. 35, p. 80 sqq.) 

 From a perusal of these papers one 

 gains the impression that science 

 has been more successful in teach- 

 ing us why the steam-engine is so 

 wasteful a machine than in show- 

 ing how it can be greatly improved. 

 It is interesting to hear that "al- 



