464, Additional Notes. 



the Inventor; but Lord Mansfield observed, *' that it was 

 not the person who locked up his invention in his scrutoire 

 that ouglit to profit by a patent for such invention, but he 

 who brought it forth for the benefit of the pubhc." 



That Mr. Ayscougii, optician, on Ludgate-Hill, was in 

 possession of one of Mr. Hall's Achromatic Telescopes in 

 1754, is a fact indisputable. — Gentleman'' s Magazine, vol. Ix. 

 Part II. for 1790, p. 890, &c. 



A new method of constructing Achromatic Telescopes was 

 invented, a few years ago, by Professor Blair, of Edin- 

 burgh. This method consists in the use of one or more flnicl 

 viedimns^ of which the dispersive powers, being opposed to 

 each other, not only correct the focal irregularities of the 

 extreme rays of the Newtonian Spectrum, but likewise those 

 near the middle ; to which former opticians had little, if at 

 all attended. From some unknown cause, however, this 

 kind of achromatic telescope has not been much used. For 

 a further account of it, see the Transactions of the Royal 

 Society of Edinburgh, vol. iii. 



Telegraph, p. 56. 



Mr. Jonathan Grout, of Massachusetts, in 1799, in- 

 vented a Telegraph on a plan which is said to be essentially 

 different from any now in use in Europe. It has been for 

 some time in operation between Boston and Martha's Vine- 

 yard, at which distance (90 miles) Mr. Grout has asked 

 a question and received an answer in less than ten minutes. 



Astronomy. ^ 



Newton, p. 5S. 



Among the honours of the eighteenth century, it /ought 

 to be considered as none of the least, that the immortal New- 

 ton lived the last 27 years of his life, and closed his glorious 

 career in this age, Tlie character of this stupendous Genius 

 is'too well known to require any details on the subject in this 

 place ; but as his name so frequently occurs in these volumes, 

 and especially in the section on Astronomy, it may not be 

 improper to compress into a few lines the following facts and 

 dates concerning him. — He was born in Lincolnshire, in the 



