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I. An Account of ObferVations made on 'Board the 
Chatham-Yacbt, Auguft 30 th and 3 \jl, and 
September 1 ft, 1 in purfuance of an Or- 
der made by the Qfight Honourable the Lords 
CommiJJioners of the Admiralty , for the Trial of 
an Inftrument for taking Angles, defcribed in 
Philofophical Tranfa&ions, "Numby 420. 
By John Hadley, Efq, Vice-Brefident of the 
Royal Society. 
I N May, 1731* I communicated to the Society 
the Defcription of a new Inftrument for taking 
Angles, and produced a Specimen of an Inftru- 
ment made accordingly. Several of the Gentlemen 
to whom it was (hewn, as well then as at other 
times, entertained a favourable Opinion of the Pro- 
bability of its lifefulnefs, particularly our worthy 
Vicc-Prefident Dr. Edmund Halley , Aftr. Reg. and 
the Reverend Mr. fames Bradley , Aftr. Pr. S. 
not only exprefled their Defire that Trial Ihould be 
made of it at Sea, but promifed the Favour of their 
Company and Afiiftance on that Occafion. 
The Inftrument produced at the Society was made of 
Wood, according to Fig. IV. l’ranfaSl. N° 410. of the 
’forementioned Defcription, and was intended chiefly for 
taking Altitudes of the Sun, Moon and Stars, from the 
vifible Horizon, either forwards or backwards j I there- 
fore procured another to be made of Brafs by Mr. J. 
Z z SiJfon % 
