Mr. Harvey's experimental inquiries , &c. 311 
and (excepting in a very few cases, where the peculiar form 
of a ship prevented ) at the constant height of the binnacle 
above them. 
To connect the different stations together, they were so 
arranged, as to fall in longitudinal and tranverse vertical 
planes, the positions of which were referred to three rectan- 
gular co-ordinate planes, having their common origin at A , 
Plate XV, fig. 1. Of these planes, that which passed in an 
horizontal direction through riA2, was assumed at an ele- 
vation of 14.5 feet above the plane of the water section, 
the draught of water forward being 8.5 feet, and abaft 13 
feet. The longitudinal co-ordinate plane passing through 
FIAT, Plate XVI, fig. 1, was 16 feet from the middle sec- 
tion, the extreme breadth of the ship being 30.5 feet; and 
the corresponding transverse plane passing through SAf 
Plates XV, XVI, fig. 1, 2, was 41.7 feet abaft the centre of 
main mast, on the upper deck. 
The first plane supposed to intersect the ship, was one in 
a vertical position, passing through its principal axis, and con- 
sequently parallel to the longitudinal co-ordinate plane. This 
plane intersected the poop and forecastle in cl a', fig. 1 , Plate 
XV. ; the upper deck in / 3 "%", fig. 2, Plate XV. ; and the lower 
deck in <y" a'", fig. 3, Plate XV. ; the section produced thereby, 
being fig. 1, Plate XVI. parallel to this plane, and at eight feet 
from it, on the starboard and larboard sides of the ship, two 
other planes were supposed to pass ; the former intersecting 
the before-mentioned decks in B' U, B" L", D'", L'", and the 
latter in U l' , b'l", d" 1 , l fig. 1,2. and 3, Plate XV., and pro- 
ducing the sections fig. 2 and 3, Plate XVI. From thenar- 
rowness of the ship, in the after part of the poop, the fore- 
