1S15.] On Dr. Wells's Essay on Dew, 251 



Article II. 



On Dew. By Dr. Wells, 



(To Dr. Thomson.) 

 SIR, 



My Essay on Dew has lately been honoured in the Quarterly 

 Review with a Criticism by Dr. T. Young, the depth and variety of 

 whose knowledge entitle him, perhaps, to be considered as the 

 most learned man in this country. I mention his name thus 

 openly, because I am confident, tliat he has too much of the spirit 

 of an English gentleman ever to desire to conceal his being the 

 author of any publication, in which he discusses the merits of a 

 literary work of another private person. With respect to the criti- 

 cism of my work, indeed, he clearly shows, that he is the writer of 

 it, by the manner, in which he speaks of his own works at its 

 close. 



I am necessarily much pleased with the general commendation, 

 which has been bestowed upon my Essay by one of his high rank in 

 literature. As several of his observations, however, lespecting it 

 do not appear to me entirely just, 1 beg leave to make a reply to 

 these through the medium of your Journal. 



I. Dr. Young has called my theory a simple and olvmis conse- 

 quence of principles deduced from the discoveries, concerning heat, 

 by Mr. Leslie, and other observers. On this point 1 shall offer a 

 few remarks, 



1. The Inquiry of Count Rumford, and the Essay of Mr. 

 Leslie, were both published in 1804, and in these works are to be 

 found all the new facts relating to heat, which I have taken from 

 others in forming my theory of dew. Whether Count R. ever after- 

 wards treated of atmospherical appearances is unknown to me ; but 

 Mr. L. published, nine years after his Essay, a work on heat and 

 moisture, in which, agreealily to the opinion of Aristotle, the pro- 

 duction of dew is attributed to the condensation, by the cold of the 

 night, of water}' vapour diffused through a considerable portion of 

 the atmosphere. Now, when the great ingenuity of Mr. L. is con- 

 sidered, if the theory of dew, which I have proposed, be an ubvmis 

 consequence of his own discoveries, it would assuredly have occurred 

 to him, in that long space of time, since he has shown, that the 

 subject of dew had in the meanwhile occupied his attention. 



2. Your own various publications demonstrate, both that you are 

 well acquainted with the modcra discoveries respecting heat, and 

 that you have attended closely to atmospherical appearances; yet I 

 remenjbcr, that you asked me, at an accidental meeting, shortly 

 before the publication of my Es.say, what my opinion was on the 

 fijrniation of flew, giving as a reason, that you were yourself igno- 

 rant of its cause. 



