342 Examination of Lalande's Remarks on 



graph, as being quite contrary to what I had long before 

 read and believed of the 40-feet telescope in the garden at 

 Slough, that I had again recourse to the Philosophical 

 Transactions, in order to refresh my recollections about it. 

 There we meet with accounts of Dr. Herschel's observations, 

 with that telescope, on the planet Saturn ; on its ring ; on 

 accurate measures of the ring j on its shadow on the body 

 of Saturn; on one of the most curious nebulae, &c. most 

 evidently proving the paramount excellency of this telescope 

 over his former ones, in regard to that kind of power and 

 performance which he had steadfastly in contemj-^lation in 

 its original construction, and which his consummate expe- 

 rience and skill, in every thing relating to vision, pointed 

 out to him as an acquisition well deserving of the most ar- 

 duous pursuit. 



But his success in this is rendered still more unquestion- 

 able by several passages, in the same volumes, where he 

 gives an account of his discovering the sixth and seventh sa- 

 tellites of Saturn, solely by the assistance of that telescope, 

 which could never have so availed him had Mr. Lalande'i 

 account of it been at all well founded. 



Some of these passages shall now be quoted, that the 

 reader, if he pleases, may confront them with the foregoing 

 extract from Lalande's History. 



From the Philosophical Transactions of the Royal Society 

 of London for 1790, p. 10 : — " In hopes of great success 

 with my 40-feet speculum, I deferred the attack upon Sa- 

 turn till that should be finished; and having taken an early 

 opportunity of directing it to Saturn, the very first moment 

 1 saw the planet, which was the 28th of last August, I was 

 presented with a view of six of its satellites, in such a situ- 

 ation, and so bright, as rendered it impossible to mistake 

 them. The retrograde motion of Saturn amounted to nearly 

 4-L minutes per day, which made it very easy to ascertaia 

 whether the stars I took to be satellites reallv were so; and 

 in about two hours and an half I had the pleasure of find- 

 ing, that the planet had visibly carried them all away from 

 their places." 



Philosophical Transactions 1790, page 474: — "Sept. 17. 



Forty- 



