359 
Triclinic-pinacoidal. 
a obkre= 1,800 dE 0: 
A= 9b at! Med 
B= 101203! EEE 
EBT -) a= She 
Forms Observed: c= $CO1}, large and lustrous, sometimes a little 
curved; a = {100}, narrower, but very lustrous; m= {i10! and 
o = {ll}, almost equally well developed, and yielding good reflexes; 
s = {011}, small, but well measurable; this form is often absent. 
Further sometimes again: = }101!, very narrow. The aspect of 
the erystals is tabular, thin plates parallel to c, and often elongated 
in the direction of the b-axis. 
Angular values: Observed: Calculated: 
axe k0OR NGO 7898 — 
c:o= (001): (111) =* 62 28% 
a:m= (100): (110) =* 79 13 a 
c:m= (001): (110) =* 77 25 ™ 
o:m= (111): (110) =* 54 10% = 
a:0=(100):(111)= 56 48%» 56°47’ 
o:s=(111):(11)= 44 19% 44 10 
ss a= (Olt): (00)= - 79.8 79 1% 
a:r==(100): (101) = 59 16 59 7 
r:c={(l01):(001)= 42 6 42 15 
Sve — (Obl) (008) = — 50 52 
No distinct cleavage was observed. 
On {001} the extinction-angle is 8° with respect to the edge a: c. 
In convergent polarized light one hyperbola is visible at the border 
of the field. 
The specific gravity of the crystals is: 1,530 at 17° C.; the equi- 
valent-volume is therefore: 229,54, and the topical parameters are 
calculated at: %: :w = 8,6739 : 4,7934 : 6,2983. 
§ 13. XI. p-Toluene-sulpho-piperidide. 
Structure: 
CH; 
SO... NCsHio 
This substance, which melts at 98° C., was obtained from ether 
in the form of large, flat, colourless, very lustrous crystals of ree- 
