jgo Gen . Roy’s Account of 
one of a circular form for the body of the inftrument ; and 
the other of an oblong fquare figure, for the tranfit telefcope. 
Within this laft box there is one of mahogany, that holds all 
the fmaller parts of the apparatus. The ftand, Reps, flools, 
pullies, ropes, tent, and canopy for the fcaffold, &c. &c. 
weighed at leaft as much more. The whole attirail was tran- 
fported from place to place, in a four-wheeled fpring carriage, 
drawn by two, and lometimes by four horfes. The carriage 
part, originally that of a crane-necked phaeton, was prefented, 
with his ufual liberality, by Sir Joseph Banks; and upon it 
was built a kind of caravan, covered with painted oil-cloth, 
whereby every thing within was kept dry and fecure. 
\ Y • x ' ' ' i -\ ■ 
SECTION THIRD. 
Defcription of various articles of machinery made ufe of in the 
trigonometrical operation referred to in Plate VII. Alfo the 
dijtinftion of the Jlations into two fets , thofe of the fecond fet 
being referred to in Plate VI [I 
i 
Article I. Portable Scaffold. 
IN the account of the meafurement of the bafe on Houn- 
flow Heath we have fliewn, that the furfaceof that remarkable 
plain is not elevated more than fifty or fixty feet above the mean 
level of the fea. From this fmall elevation, and the circum- 
ftance of its being furrounded, almoft on every fide, with lofty 
trees, it was from the beginning fufficiently obvious, that, in 
order to be enabled to make the oblervations of the collateral 
Rations 
