the Trigonofnetrical Operation . * j ^ 
obferver, as well as an able and indefatigable calculator. This 
teftimony, which is juftly due to his merit, joined to the fpe- 
cirfien which he gives of his mathematical abilities in the fifth 
fed lion of this Paper, can fcarcely fail of making him better 
known hereafter; and it is hoped, that he will have opportu- 
nities of exerting his talents, by affifiing in the continuation of 
the future operations that are projected and recommended to 
be carried on in the conciufion of this Memoir- the various 
parts of which are arranged as follows : 
SeH ion Fuji-... 
Defcription of the apparatus made ufe of in the meafure- 
meat of the bafe of verification in Homney Marfh, with the 
hundred-feet Reel chain, in the autumn of 1787, with the refult 
of that operation. Reference to be had to Plate I. and II. and 
alfo to the table containing the general detail of the mea- 
furement. 
Section Second 1 
General defcription of the great infer u merit with which the 
angles in the recent trigonometrical operation were obierved ; 
ihewing alfo its various adjpRments for practice. Reference to- 
be had to Plate III. a general view of the entire machine * 
Plate IV. a plan and two feclfions of it ; Plate V. various parts 
lepiefented on large fcale.s;. and Plate VI. the microfcopes and-’ 
eye- pieces. 
Section Third. 
Defcription of various articles of machinery made ufe of m 
the courfe of the trigonometrical operation, referred to in Plate 
V1L Alio- the dIRinclion of the Rations into two lets'; thole 
ot the fecond fet being referred to in Plate VIII. 
