Hiftory ofAjironomy for the Year i8oo. I65J 



Trlgdnometry, aiid Practical Geonietrvj lo the end of the 

 16th century; Gottijigen 1796. Vol.11. Perfpedive Geome- 

 trical Analyfis, and ihe higher Geometry, Mechanics, Optics^ 

 and Aftronomy ; firft period towards the end of the i6th cen- 

 tury. Appendix to the firft volume, ibid. 1797, large o6lavOi 



XIL Hijlory of AJironomy for the Year i860. By JeromJE 

 De Lalande. 



[Concluded from Page 15.] 



V^. CAROCkE finiftied in the month of May a tfelefcope 

 of 23 feet, conftru6ied without a fmall mirror, in the fame 

 manner as thofe of Lemaire and Herfchel ; and he is now 

 employed in making for another a fpeclilum of platiha 7 \ 

 inches in diahleter. 



C. Treiriel has begun a new ftand for the telefcOpe of 

 2Z feet, much firmer and more coiivenient than thofe before 

 employed. 



A terrace has been begun towards the fouth on a level 

 with the lower hall of the obfervatory, foi: placing the tele- 

 fcope upon when carried out : nothing is wanting to com- 

 plete it but the laft cdurfe of the materials. 



Brother Noel, a BenedicStine, fmlflied, in 177^, a felefcope 

 the fpeculum of which had a, focus of 24 feet 4 inches, and 

 \vhich was 22! inches in diameter*. He pretended that 

 this telefcope magnified 430 times ; but Sir George Shuck- 

 burgh edimated its magnifying power only at 200. Noel 

 valued this inftrument at 8o,ood francs^ biit Louis XV. haa 

 expended upon it more than 500,000. 



The fmall fpeculum was convex, ih imitation of Caffe- 

 grain's, and had five feet real focus ; which made the length 

 of the telefcope lefs. The eye-glalTes of 8 and 24 inched 

 focu^ could magnify 528 times ; but it was not fufficiently 

 good to bear that degree of power. 



He miftrufled aflronomers, and would not fuffer me to view 

 Jupiter through his telefcope: '^ If you find it a good one,''^ 

 faid he, " you will add nothing to my credit, for I am ai- 



■* Connoijfuncts des tempi 1775, p. 339. 



Vol. IX. O lowed 



