LUNAR ATMOSPHERE. IJ/ 



I have been informed, that the only Intimation commonly Custom of the 

 siven to the author of a paper which is not to be printed in °^^ ociety, 

 the Philosophical Transactions is a simple letter of thanks, 

 ivithout any further notice respecting it. But the Society 

 does not usually return thanks for a lecture read by appoint- 

 ment : hence therefore must have arisen the omission, which 

 Professor Yince seems to think so inexcusable. 



I am sorry that any of your correspondents should have Intentions of 

 considered my remarks as written in an improper spirit: ^^" °^' 

 you, I believe, were not of that opinion; and I can only 

 say, that if that correspondent could have pointed out to 

 me any objectionable expressions, I should most willingly 

 have omitted them. My only motive was the wish to repel 

 an unjust attack ; my observations tended more to impute 

 inattention than inability to the party concerned ; and I am 

 at this moment ready to allow that a very great mathema- 

 tician may not only be materially mistaken, but may reso- 

 lutely defend his errour, when it is discovered by another 

 person; and that he may even have so short a memory, as to 

 forget, while he is defending himself, what he had before 

 written on the same subject. 



I am. Sir, 



Your very obedient servant, 

 7 May, 1808. DYTISCUS. 



IX. 



Calculation of the Rate of Expansion of a supposed Lunar 

 Atmosphere. By a Correspondent. 



To Mr. NICHOLSON. 

 SIR, 



JLT has been a subject of inquiry among some who are at- Inquiry into 



tached to astronomical speculations, whether or no, if the ^!'^ !?'^'^L°^< 

 , p ' the Earth's at- 



moon had ever been possessed of an atmosphere equally traction upon 

 dense with that of the Earth, she coidd have retained it, with- the atmosphere 



.,,,.... ,. 1 -,-. , , of the moon. 



out a very sensible dimmution, in consequence or the Earth s 



attraction, upon the supposition of the infinite dilatabihty of 



the 



