CALCULUS OF PARTIAL DIFFERENCES. 35 



the main pleasure bestowed by it is the gratification which, by 

 a law of our nature, we derive from contemplating scientific 

 truth, when indulging in the general views which it gives, 

 marking the unexpected relations of things seemingly un- 

 connected, tracing the resemblance, perhaps identity, of 

 things the most unlike, noting the diversity of those appa- 

 rently similar. This is the true and primary object of 

 scientific investigation. This it is which gives the pleasure 

 of science to the mind. The secular benefits, so to speak, the 

 practical uses derived from it, are wholly independent of this, 

 and are only an incidental, adventitious, secondary advantage. 

 (See Introductory Eemarks to this volume.) 



It is an illustration of the happiness derived from mathe- 

 matical studies, that they possess two qualities in the highest 

 degree, not perhaps unconnected with one another. They 

 occupy the attention, entirely abstracting it from all other con- 

 siderations ; and they produce a calm agreeable temper of mind. 



Their abstracting and absorbing power is very remarkable, 

 and is known to all geometricians. Every one has found 

 how much more swiftly time passes when spent in such 

 investigations, than in any other occupation either of the 

 senses or even of the mind. Sir Isaac Newton is related to 

 have very frequently forgotten the season of meals, and left 

 his food awaiting for hours his arrival from his study. A 

 story is told of his being entirely shut up and disappearing, 

 as it were eclipsed, and then shining forth grasping the great 

 torch which he carried through the study of the heavens ; he 

 had invented the Fluxional Calculus. I know not if there be 

 any foundation for the anecdote ; but that he continually 

 remained engaged with his researches through the night is 

 certain, and that he then took no keep of time is undeniable. 

 It does not require the same depth of understanding to expe- 

 rience the effects of such pursuits in producing complete 

 abstraction ; every geometrician is aware of them in his own 

 case. The sun goes down unperceived, and the night wanes 

 afterwards till he again rises upon our labours. 



They who have experienced an incurable wound in some 



D 2 



