J79'* ^^^ Bs*coi». 295 



*»* Dr Anderfon, in a fubfequent letter addrefled to Rich- 

 ard Molefworth, Efq; informs hire tiiat he had made an im- 

 provement on the filk reel, defcribed in the French Encyclo- 

 pedic^ in which the fecond axle flands diagonally to the frame, 

 v/hich expofes tlie threads to be broken as they pafs over the 

 hooks at nearly a right angle. To remedy this, he caufed a 

 inortoife to be made in the middle of the comer and goer, 

 through which an inverted T may be moved up or down at 

 pleafure. In this way the filk is brought over the hooks at 

 an angle as obtufe as may be found neceflary, and the mo- 

 tion of tiie wheels arnended by placing th'^m at right angles 

 to each other, with the axle prallel to the frame. 



For the Bee. 



Beacon on the Bell Rock, 



S I R, 



Since my firrt going to fca-, which is twenty-fix years, I have 

 wiihed that fome method might be thought of to put a bea- 

 con on that fingularly dangerous rock called the Gape, or Bell- 

 rock, which lies off St Andrew's Bay^ and is about twelve 

 miles from Fifenefs, and nearly the fame difbance from the 

 Red-head, and not far from the entry into the river Tay, 

 The difficulty of fixing a beacon here is very great, as the 

 fea fall out of thirty fathom water on the eafl fide of this 

 rock, would be fo heavy as to beat down an ordinary beacon 

 in a very fliort time ; aijd this difficulty is encreafed by the 

 neceffity of having bells at its top, to give the alarm to vefWs 

 which (hall approach it in the dark, without which it would 

 but ill anfwer the purpofe. 



I have long revolved this fubjeft in my mind, before I could 

 difcover how thefe very great difficulties could be overcome, 

 and am now more than happy In being able to afl'ure you, and 

 the public through your means, thofe elpecially who are interefl- 

 ed in navigation, that I have at lall: overcome all obftacles, and 

 have completed a model of a beacon for tliat purpofe, on princi- 

 ples that I am fatisfied will certainly effect the purpofe intended, 

 wliJch I am ready to fliow to any perfon who is a judge of 



