584 REMARK O-N MR. MOORE'S PAPER ON ROCKET** 



These observations will be found, no doubt, capable of 

 frequent application. It was from not being acquainted 

 with them, that Mr. Chevreul has given an explanation of 

 the action of caloric on indigo, which is by no means sa- 

 tisfactory. 



XII. 



Remark on Mr. Moore's Paper on the Motion of Rockets. 

 In a Letter from a Correspondent. 



To Mr. NICHOLSON. 

 SIR, 



Remark on Mr, A OUR readers undoubtedly feel much indebted to Mr. 



Moore's paper lyjoQi-g for soiTie ingcpious papers upon the motion of 

 rockets. As the subject is an important and curious one, 

 it is highly deserving of accurate investigation. On this 

 account I am desirous of pointing out to Mr. Moore's no- 

 tice, as early as possible, an errour iqto which he has in- 

 advertently fallen. In his investigation of the resistance 

 opposed to a cylinder moving in a fluid, in a direction in- 

 clined to the axis, he expresses the sine of the angle P T « 

 (see fig. 2, Plate vii,) in terms of the sines and cosines 

 of PTQ, andQTw; forgetting that the three angles are 

 in dffferefit jdanes^ and consequently that the trigonome- 

 Irical formula, to which he refers, will not apply, 



I am, Sir, 



Yours, &c. 



ZENO. 



INDEX 



