Gonioinetric Vrohlems. 129 



The emperor having granted some instruments to the 

 Turin observatory, M. Charles Dominique Marie dii Chayla 

 has been attached to it. He set oat for Turin in September 

 1803, after having for some time aitcnded the observatory 

 of Paris. 



The 22 -foot telescope of the observatory has been refitted 

 by M. Caroche, but the stand of it is too embarrassing, 

 and they propose making another, after having expended 

 50,000 francs for the first: M. Caroche has discovered that 

 it is very difficult to place a mirror weighing 400 pounds in 

 such a wav as not to change its form or position when tRe 

 telescope is pointed at different altitudes. ^ 



The 40-foot telescope of Mr. Hersehel has not yet fur- 

 nished the extraordinary results we expected from it. I 

 wrote to him that I was desirous of coming to England to 

 visit this prodio;ious instrument, as soon as he wrote me 

 thai he had no objections : I have not yet received his an- 

 swer. As Mr. Hersehel is now 6S years of age, I am afraid 

 he will not be able to satisfy himself, and that he will not 

 find a successor capable of terminating completely so diffi- 

 cult an enterprise. 



[To be continued.] 



XVII T. Prohlems on the Redi/.ction of Angles. By T. S. 

 Evans, F.L.S., of the Royai Military Academy, Wool- 

 wich. 



[Coiiiiiuied from p. f!4.] 



Problem VI. 



JL o find the relation between the angles ASC, FSE, ASF, 

 and CSE, when the plane AE is perpendicular to the tri- 

 angle ASF, and the figure AE a parallelogram. (Fig. 12.) 



Bv the Problem, p. 29, we have CS^ -f- ES^ - 2 CS. ES. 

 c, CSE = EC« and AS' + FS' - 2 AS. FS. c, ASF = AF»; 

 but as AF*=FC', therefore these two equations are equal to 

 each other. Again, CS = AS /, ASC, and ES = FSf, FSE ; 

 substituting these for their equals, and putting the two equa- 



Vol. 28. No. 110. July 1807. I l'""s 



