— 123 — 
log. 1= 0,2769205 
log. tg<ÿ'z= 1,8673583 
”* 1 -J rj 
0,1442788 .- = 1,4 = g.i = 570 = G 6> 
ZONE PARALLÈLE A 2a. 
Notation du prisme f f f' f”. Soit f = okl. 
On a : 
b c l c tg\K 
fg H- = 27 0 42' fe = F <3IA== T‘ 
log. tg [x = 1,7201690 
log. p’= 0,0204732 
log. 1,6996958 . j-=| . f = 021 = 
Fig. 4. 
toi— 
