230 



APPENDIX. 

 •*' voyage from thence to England, as we found on our 

 " return. By this means we were induced to give the 

 " preference to the watch, and to conclude that the 

 " longitude found by it was not very different from the 

 '' truth. 



" The principles on which this watch is conftrufled, as 

 *' I am informed by the maker, Mr. Arnold, are thefe: the 

 " balance is unconnected with the wheel-work, except at 

 ** the time it receives the impulfe to make it continue its 

 *' motion, which is only while it vibrates io°out of 380", 

 " which is the whole vibration ; and during this fmall 

 ." interval it has little or no friftion, but what is on the 

 *' pivots, which work in ruby holes on diamonds ; it has 

 ^' but one pallet, which is a plane furface formed out of 

 " a ruby, and has no oil on it. 



" Watches of this confl:ru6tlon go whilft they are wound 

 " up ; thev keep the fame rate of going in every pofition, 

 ^' and are not affeded by the different forces of the fprlng : 

 ^' the compenfation for heat and cold is abfolutely ad- 

 "juftable. 



" Time-keepers of this fize are more convenient than 

 *' larger, on feveral accounts; they are equally portable 

 *' with a pocket watch, and by being kept nearly in the 

 *' fame degree of heat, fuffer very little or no change from 

 ■*' the viciffitudes of the weather. 



" This 



