360 
tangular shape. They are well built, beautifully translucid, and 
allow very accurate measurements. 
Fig. 11. p-Toluene-sulpho-piperidide. 
Rhombic-bipyramidal 
a:6:¢= 0,7474: 1: 0.3790. 
Forms Observed: a= }100}, predominant and yielding good reflexes ; 
m = {110} and 5= {010}, large and very lustrous; p= {120}, very 
narrow; r= {101}, large and giving good reflexes. 
Angular Values: Observed: Caleulated : 
a:m= (100): (110) =* 36946!/2’ — 
a:r = (100): (101) =* 63 6% = 
m: p = (110):(120) = 19 23% 19°26}/2’ 
p:6=(120):(010)= 33 50 33 47 
r:r=(101):(101)= 53 46% 53 46%/s 
No distinct cleavage was found. 
The optical axial plane is {001}, with the b-axis as first bisector; 
the dispersion, of rhombic character, is very appreciable: 6 << v. The 
apparent axial angle is only small. 
The specific weight of the crystals is: 1,281 at 15° C.; the equi- 
valent-volume therefore: 186,57, and the topical axes become: 
4: p:@ = 6,5029: 8,7005 : 3,2967. 
§ 14. XII. Nitro-p-Toluene-sulpho-piperidide. 
The substance melts at 108° C., and crystallizes from ethylacetate 
in splendid large, somewhat pale yellowish, translucid, very lustrous 
erystals. They are well built, and allow good measurements. 
