lx INTRODUCTION. 



rack- work, and the laft Mr Short ever made, which proved 

 a very excellent inftrument ; alfo an achromatic telefcope 

 by Dolland, nearly equal to a three-feet reflector, with a 

 foot, or itand, very artificially compofed of rulers fixed to- 

 gether by fcrews. I think this inftrument might be im- 

 proved byfhortening the three principal legs of it. If the 

 legs of its ftand were about fix inches fhorter, this, without 

 inconvenience, would take away the little make it has when 

 ufed in the outer air. Perhaps this defect is not in all te- 

 lefcopes of this conftruction. It is a pleafant inftrument, 

 and for its fize takes very little packing, and is very ma- 

 nageable. 



I have brought home both thefe inftrumems after per- 

 forming the whole journey, and they are now (landing in 

 my library, in the moft perfect order ; which is rather to be 

 wondered at from the accounts in which moft travellers 

 feem to agree, that metal fpeculums, within the tropics, fpot 

 and ruft fo much as to be ufelefs after a few observations 

 made at or near the zenith. The fear of this, and the fra- 

 gility of glafs of achromatic telefcopes, were the occafion 

 of a conftderable expence to me; but from experience I found,, 

 that, if a little care be taken, one reflector would be Sufficient 

 for a very long voyage* 



From Paris I received a time-piece and a (top- watch made 

 by M. Lepeaute, dearer than Ellicot's, and refembling his in 

 nothing elfe but the price. The clock was a very neat, 

 portable inftrument, made upon very ingenious, flmple prin- 

 ciples, but fome of the parts were fo grofsly neglected in 

 the execution, and fo unequally finifhed,. that it was not 

 difficult for the meaneft novice in the trade to point out the 



caufe 



