434 
DE. A. W. HOFMAXX OX THE PHOSPHOEUS-BASES. 
According to Naumax^'^ : — 
J:c=l: 0-8583; y=61° 2'. 
Forms observed : — 
OC P QO, oc P oc, OP, cc P. 
According to Weiss : — 
0-8583; «oc=118°58'. 
Forms observed : — 
«: co ^; goc ; oo a: h : qoc, zc. a\ och \ c \ a\h c. 
According to Levy : — 
Forms observed: — 
M M=88° 54'; 
A', g\ P, M. 
M P=109° 50'. 
The faces 0 01 present less lustre than the others, which are very bi-dhant, when the 
crystals are taken from a tube which contains a number of the crystals. In contact 
with the air they become opaque, and the faces lose their lustre, but they become again 
transparent when returned to the tube containing the other crystals. 
Cleavage 10 0 easily obtained ; cleavage 110 fibrous. 
Hardness nearly that of gypsum. 
The plane of the optical axes is parallel to [0 1 0], or to the axis of symmetry. 
Colour light yellow, with a tint of green.” 
If we endeavour to associate this compound with well-known bodies, in order to 
obtain some insight into the probable an-angement of its proximate constituents, both 
its formation and its deportment point to urea. Urea is generated by the combination 
of ammonia and cyanic acid : the yellow crystals are formed by the union of two com- 
pounds derived respectively from ammonia and cyanic acid ; in urea the facidty possessed 
by ammonia of combining with acids has been preserved ; the new compound like-vUse 
exhibits the sharply-defined characters of a monacid base. Whatever constitution be 
attributed to urea, must also be claimed for the new base. If urea be Hewed as a 
monacid diamine, 
(CO)"] 
C N,^ O = H, V N„ 
h; J 
the yellow crystals present themselves as 
(C S)" ] 
Ci3H2oNPS= (C.H^), np. 
(C,H,)(C,ll3)l 
The new compound accordingly belongs to the type urea : it may be viewed as ordi- 
nary urea, the oxygen of which is replaced by sulphur, for the hydrogen of which ethyl 
and phenyl have been substituted, wliilst phosphorus has taken the place of half tlie 
nitrogen. Regarded from this point of view, the formation of the new compound pre- 
sents considerable interest ; it offers the first example of the perfect substitution of the 
