£55 DISADVANTAGE OF JEWELLING CLOCKWORK. 



XVII. 



On the Disadvantage of Jewelled Holes in jpiockwork. In. a 

 Letter from Mr, W.Walker, to 3Ir.J. Barraui^. 



Dear Sir, 



jewelled holes ^^ sorry to have delayed so long the account you 



©fa transmit wkhed of the state in which I twice found the jewelled 



^"^ ' holes of my transit clock, when I took it to pieces: as the 



vibration had each tinae fallen off, from being on each side 



the pei-pendicular 2° 10' 10", and were then no more than 



1" 30' 40 ". 



After 15 jjj July 1805, under your direction, the clock was cleaned. 



months going, • • i .^^ /-it 



and 2 months ^^^ ^^s kept regularly going till Oct. 1800, when I went 



^^^^> from home for two nxonths:. On my return on Dec. 6th, I 



would not go. yvou^fi it up, but could not make it go even when I added 



©il fluid ex- about two pounds weight more to the clock weight. I there* 



jjewelled holes. ^^^^ took it to pieces, and found the oil very fluid in all the 



holes, except those which were jewelled, where it was almost 



black, and very glutinous. It required great force, and some 



dexterity, to draw out the spindle that carries the secondft 



Set a going hand. I set the clock going again on the 7th of Dec, and 



it immediately threw out its full vibration on each side=:2** 



10' 10"; and continued to go with its usual excellence, till 



In 10 months towards the end of Oct. 1807, when it again fell off consi- 

 again its gomg . . ° , 



affected, derably ; and gained very much on its general rate. There- 



fiiom, the foul* fore, on Nov. 23d, 1807, I again took it to pieces; found all 

 fewefiiiiV^ the jewelled holes extremely foul, black, and clogged; and 

 separated the jewels, which were strongly adhesive: yet the 

 oil on the pallets was very fluid, and in a good state in all 

 the brass holes. Before this cleaning the clock had gradually 

 thrown out less and less for two months preceding, and was 

 at this time no more than ]° 30' 40" on each side, but on 

 fresh oil being applied, it immediately became ~ 2° 10' 10 " 

 Excellence of ^^ each side; and has gone with such excellence ever since, 

 ** that I cannot forbear transcribing the latter part of my Jour- 

 nal ; 



