160 
these nodules were not observed in the coarser-grained granite ; 
granite and the white granite, and it is in the former that 
they undoubtedly reach their maximum development. 
The author, after consideration of the occurrence at 
Cape Willoughby, suggests that the following processes have 
rond piens in their production :— ; 
stallization of the main mass of granite was 
followed by the production of fissures and joints as a result 
of contraction through cooling. Into these fissures was in- 
ri 
mineralizer, water, was present, Al as a gas, below its 
critical Mie (10) 
The increased magma "pico thus originating through 
fissuring, Mie resultant effects are 
1 reduction. of s uS to expansion of the 
gas phase; concurrently a reduction of the hid 
centration of the volatile components in the mu 
ma. 
(2) yox ended in the viscosity of the silicate liquid 
T ue to reduction of the active mass of the minera 
n the liquid. 2 
(3) Gani the crystallization temperatures 
reezing points of the silicates in solution. 
; [It is to be noted here that a lowering of freezing po 
s erally accompanies a reduction of pressure, but this efe 
tle components. This latter effect apears hav Be piis 
nored or den ea by some casa Cah; Scheele! gee 
9) Loc. cit., No. Vs 
b el re was 
Below 370° O C.—the critical temperature’ for pure water. 2 ge 
editibal tóm. : ure of aee soepen eo & 
eleva cre rature t han i possesses the pure 
& dg ‘of the 7 eal temi perature » analogous to- the a evation 
Rien: Ne Neues Sehrbach. ui. B4. 17, 1903, p. pe 
