Hyland — On' the Mesolitc (Galactite) of Ken bane Head. 419 



In the case of the natrolite, as 0'5 molecule H 3 is not ex- 

 pelled until the temperature rises to 290°, the two molecules of 

 H 2 must be considered as attached to the aluminium. On the 

 other hand, the scolezite loses one molecule under 250° ; this must 

 belong to the silicium ; the other two to the aluminium. The 

 Constitution- formulae will therefore be — 



