INTRODUCTION. 



afliftance in drawing up the account of the produdions of 

 that country ; which I acknowledge with particular fatis- 

 fadion, as inftances of a very long friendfhip which I am 

 happy in an opportunity of mentioning. 



As a voyage of this kind would probably afford many 

 opportunities of making experiments and obfervations in 

 matters relative to navigation, I took care to provide my- 

 felf with all the beft inftruments hitherto in ufe, as well 

 as others which had been imperfedly, or never, tried. 



The length of the Second Pendulum in fo high a lati- 

 tude as I was likely to reach, appearing to me an experi- 

 ment too interefting to be negleded, I delired Mr. Gum- 

 ming to make me fuch an inftrument as he thought would 

 beft anfwer the purpofe. That modefty and candour which 

 always attend real merit, induced him to lend me the 

 identical pendulum with which Mr. Graham had made his 

 experiments, rather than furnifli me with one of his own 

 conftrudion ; but the judgment as well as fkill with 

 which the apparatus joined to it was contrived and exe- 

 cuted, notwithftanding the fhortnefs of the time, will, I 

 am fure, do him credit. 



The Board of Longitude fent two watch machines for 

 keeping the longitude by difference of time ; one con- 

 ftrudcd by Mr. Kendal, on Mr. Harrifon's principles ; 



the 



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