THE YOUNG SCIENTIST. 
173 
plan," Fig. 2 the "cross-sections," and 
Fig. 3 the " water-lines " of the boat. The 
line A B in Fig. 1 represents the " load 
water-line," and indicates the depth of 
the boat's immersion when laden. The 
line c D, parallel with this load water- 
line, shows the draught of the boat, and 
a horizontal line, e f, is drawn equidis- 
tant from these two lines. The vertical 
centre of the boat, so that the part of the 
hull before it is longer than that portion, 
behind it. The perpendiculars g h (at 
the bow) and i k (at the stern) are then 
drawn, and other peri^endiculars, l m and 
N o, midway between the boAV and the 
midship frame and that part of the boat 
and the stern. 
Fig. 2 (showing the cross sections) and 
PIC. 
C 5 
-4- 
2 ^ 
f 
/ y 
1 
na.7. 
FiC..6 
line ® ©' corresponds with the broadest 
part of the projected boat, at what is 
called the midship frame. In nearly all 
drawings of marine architecture the sym- 
bol © (the same as that used in astro- 
nomical almanacs to designate the earth) 
is usually employed to denote this portion 
of a vessel. The midship frame is gener- 
ally placed abaft (or behind) the exact 
Fig. 3 are drawn on the horizontal lines 
p p" and Q Q ' respectively. For Fig. 2 the 
horizontal line p p' is bisected by the per- 
pendicular R s, on each side of which the 
semi-breadth of the boat is set off at o, 
I, m. Here the line p p' indicates the 
water-line shown by a b in the sheer plan ; 
G d corresponds with the line of the great- 
est draught of the boat as at c d in Fig. ly 
