SIMPSON'S RULES 355

The area of each bulkhead now becomes the ordinate in finding the
cubic capacity and, as there are five of them, the 1𦴕 rule will apply,
the work to be arranged in the following order.

\ Ordinates Multipliers Products
a 100 1 100

6 350 4 1400

c 630 2 1260

d 450 4 1800

e 200 1 200

4760

4760 X ~
3

Total volume 95,200 cub. ft.
The displacement of this volume in salt water would be 95200-r
35=2720 tons.
A closer spacing of the bulkheads, or rather, ordinates, as it is not
necessary to actually build in the transverse areas and we have merely
shown them in the figure to help out our explanation, a closer spacing
would give a closer approximation to the actual volume.
Shipbuilders, however, prefer to calculate the enclosed volume of
a considerable part of a ship by using horizontal transverse sections
rather than vertical transverse sections as in the preceding example.
Simpson's Eules are based on the assumption that the boundary
of the curvilinear area conforms to a parabolic curve, so that results
will be only approximately correct when the cnrve departs from a
parabola.