COMETARY DISCOVERY. 



-unconnected to our imperfect vision by any discoverable law, a 

 war of passions and prejudices, governed by no apparent purpose, 

 tending to no apparent end, and setting all intelligible order at 

 defiance how soothing and yet how elevating it is to turn to the 

 splendid spectacle which offers itself to the habitual contemplation 

 of the astronomer ! How favourable to the development of all 

 the best and highest feelings of the soul are such objects ! the 

 only passion they inspire being the love of truth, and the chiefest 

 pleasure of their votaries arising from excursions through the 

 imposing scenery of the universe scenery on a scale of grandeur 

 ;and magnificence, compared with which whatever we are accus- 

 tomed to call sublimity on our planet dwindles into ridiculous 

 insignificancy. Most justly has it been said, that nature has 

 implanted in our bosoms a craving after the discovery of truth, 

 and assuredly that glorious instinct is never more irresistibly 

 awakened than when our notice is directed to what is going on in 

 -the heavens. " Quoniam eadem Natura cupiditatem ingenuit 

 hominibus veri inveniendi, quod facillime apparet, cum vacui curis, 

 etiam quid in ccelo fiat, scire avemus ; his initiis inducti omnia 

 vera diligimus ; id est, fidelia, simplicia, constantia ; turn vana, 

 rfalsa, fallentia odimus." * 



2. Such reflections are awakened by every branch of astronomy, 

 'but by none so strongly as by the history of cometary discovery. 

 No where can be found so marvellous a series of phenomena 

 :foretold. The interval between the prediction and its fulfilment 

 has sometimes exceeded the limits of human life, and one gene- 

 ration has bequeathed its predictions to another, which has been 

 filledjWith astonishment and admiration at witnessing their literal 

 accomplishment. 



3. In the vast framework of the theory of gravitation constructed 

 :by Newton, places were provided for the arrangement and ex- 

 position not only of all the astronomical phenomena which the 

 observation of all preceding generations had supplied, but also for 

 a far greater mass which the more fertile and active research of 

 the generations which succeeded him have furnished. By this 

 theory all the known planetary motions were explained, and 

 planets previously unseen were felt by their effects, their places 

 ascertained, and the telescope of the observer guided to them. 



But transcendently the greatest triumph of this celebrated 

 theory was the exposition it supplied of the physical laws which 

 govern the motions of comets as distinguished from those which 

 prevail among the planets. 



.4. It is proved in the propositions demonstrated in the first 



* Gic. de Fin. Bon. et Mai.., ii. 14, 



L 2 147 



