40 Letter from a Reviewer. 



to Dr. Thornton for making him acquainted with facta 

 which had escaped his notice, and which are not mentioned 

 in most, if any, of our English professed treatises on astro- 

 nomy. In his younger years he studied the mathematical 

 principles of that very extensive science, in connection with 

 the other essential parts of what is esteemed a regular edu- 

 cation. Professional and other circumstances soon directed 

 his chief attention to other pursuits. But, though occupied 

 in what to him were more important concerns, he did not 

 entirely relinquish what had given him a high pleasure. 

 In subsequent periods of his life he recalled to his memory 

 the knowledge which he had formerly acquired, by care- 

 fully reading Rutherford's System of Natural Philosophy 

 and Nicholson's Introduction ; and a very little time before 

 he engaged in the very irksome task of reviewing the vaunted 

 Illustration of the Sexual System of Linnaeus, he had hap- 

 pened to take a cursory view of professor Vince's Complete 

 System of Astronomy. In these standard works there is 

 not a word concerning a satellite of Venus ; and so little 

 credit has its existence obtained with our English astrono- 

 mers, that Mr. Vince, though he gives a detailed account 

 of Cassini's dispoveries, passes it (Over in silence. There- 

 viewer was not ignorant that, among other advantages ex- 

 pected to be derived from the two transits of Venus over the 

 sun, which, fortunately for the astronomers of the time, hap- 

 pened within eight years of each other, it had been sug- 

 fested, that if Venus have a moon, it must then be seen. 

 Jone of the able astronomers who solicitously viewed this 

 interesting phenomenon in different parts of the world, per- 

 ceived any appearance of a secondary planet. The reviewer^ 

 therefore, believed that the question, which in his appre- 

 hension had been only a speculative one, was completely 

 decided. But he feels no reluctance to confess, that had he 

 been aware of the observations related in the Encyclopaedia 

 pritannica, or if he had happened to consult Dr. Rees's 

 folio edition of Chambers, to which he had readier access, 

 that passage which Dr. Thornton has exclusively selected 

 for animadversion would not have been written. He has 

 made a blot which, he trusts, will not be thought.very dis- 

 graceful to one who never professed himself a thorough pro- 

 ficient in the game. This blot Dr. Thornton has fairly hit; 

 and he has a right to avail himself of it as far as it will go. 

 But he must make many more such hits, or he will not save 

 his gammon. The moon of Venus, as he himself owns, 

 has only a very remote connection with the object of his 

 work. And he has not attempted to invalidate any of the 

 6 serious 



