TO OUR READERS AND CORRESPONDENTS. 



Wk have received a paper from Mr. Meikle, " On the Relation 

 between the Density, Pressure, and Temperature of Air, and on Expe- 

 riments regarding the Theory of Clouds, Rain, &c. ; with a Conjecture 

 about Thunder and Lightning," which an accidental circumstance has 

 obliged us to postpone. It will be found to bear upon his Reply to 

 Mr. Ivory, which we now publish. 



The deposit upon the Specimen from the margin of one of the Lakes 

 of Killarney, is Argillo-siliceous. The Chalk contains Alumina, but no 

 Magnesia. The Pyrites is common. 



In Mr. Addams' paper on the Sap of the Rose, published in our last 

 Number, p. 149, line 9 from the bottom, for ** oxalate of ammonia," 

 read " oxalate of lime,"' 



An account of the proceedings of the Royal Society, at their Anniver- 

 sary Meeting, will be found in the Literary Gazette for the following 

 Saturday. 



The Drawing of an Ornamental Aviary, illustrative of the paper 

 which we printed in our last Number, by J. C. Cox, Esq., reached us 

 too late for insertion. 



We request "X." to refer to our private letter upon the subject of 

 Gas-engines. The whole affair is as we have there stated it, et prceterea 

 nihil. 



Our attention has been directed, by more than one Correspondent, to 

 the operations lately carrying on in the Chelsea Water Company's 

 Reservoir in the Green Park. We wish to see them terminated before 

 we say more. In the mean time, we beg the writer, who dates from 

 Paddington, and who deprecates the use of reservoirs, to recollect that, 

 if these thousands of cartloads of filth had not been deposited where 



