J. I. HAYCROFT. 



c 



F + K+ 2?r (*. -**-*•) 



- 22-5 



-2 



21, 

 + 2(P 1 + P 2 + P 3 ) (^ + ^_5) 



= F + K+ J^i (P 3 -P 4 -P 5 ) 



22-5 



24 1, 

 H D 2 



2 1, 



/ r> h 2 d \ / \ 



+ \ 2^7 + TIT ) ( 5 (Pi + P. + PaJ + Pi + P.) 



B 



F + K + C 



+ 2?i (p 2 -p 3 -p 4 -p 5 ) 



^ A i 



/ D H 2 D \ 



+ V 2~S7 + "8IT ) (7Pi + 7P 2 + 5P 3 + 3P 4 + P 6 ) 



A 



F+K+C+B 



+ 2?i;(Pi-p 2 -p 3 -p 4 -p 5 ) 



+ ( 2X + TIT) 2 ( 9 Pl + 7P 2+ 5 P3 + 3 P 2 +P 5 ) 



The values of Ay} of these sections have the same values, but 

 with contrary signs, hence the equality Ay x = Ay} or Ay x — 

 Ay} = becomes 2Ayj = 



