1 8.  Referring  to  the  previous  question,  find  the  area  in  square  feet  of  the
portion  of  the  plan  between  the  ordinates  \\  and  5$.
Ans.  1067.
19.  The  half-ordinates  of  the  midship  section  of  a  vessel  are  22-3,  22'2,
217,  2O'6,  17*2,   13*2,  and  8  feet  in  length   respectively.     The  common
interval  between  consecutive  ordinates  is  3  feet  between  the  first  and  fifth
ordinates,  and  i'  6"  between  the  fifth  and  seventh.    Calculate  the  total  area
of  the  section  in  square  feet.
Ans.  586 '2  square  feet.
Areas,    Volumes,    Weights,  Displacement,  etc.        39


20.  Obtain  the  total  area  included  between  the  first  and  fourth  ordinates
of  the  section  given  in  the  preceding  question.
Ans.  392 -8  square  feet.
21.  The  semi-ordinates  of  the  load  water-plane  of  a  vessel  are  0*2,  3-6,
7-4,  10,  n,  107,  9-3,  6'5,  and  2  feet  respectively,  and  they  are  15  feet
apart.     What  is  the  area  of  the  load  water-plane  ?

Ans.  1808  square  feet.
22.  Referring  to  the  previous  question,  what  weight  must  be  taken  out
of  the  vessel  to  lighten  her  3^  inches  ?

What  additional  immersion  would  result  by  placing  5  tons  on  board  ?

Ans.  15  tons  ;  I'l6  inch.
23.  The  "tons  per  inch  immersion"  of  a  vessel  when  floating  in  salt
water  at  a  certain  water-plane  is  44-5.     What  is  the  area  of  this  plane?

Ans.  18,690  square  feet.
24.  A  curvilinear  area  has  ordinates  3  feet  apart  of  length  97,  lo'o,  and
1 3 '3  feet  respectively.     Find —

(1)  The  area  between  the  first  and  second  ordinates.
(2)  The  area  between  the  second  and  third  ordinates.
(3)  Check  the  addition  of  these  results  by  finding  the  area  of  the  whole

figure  by  Simpson's  first  rule.
