134 



Norman L. Silvester — Igneous Complex of 



undoubtedly much, greater and more prolonged than was actually 

 required for the purposes of the experiment, the temperature of the 

 kiln being not less than 1,200 degrees Cent. The bubbles are too 

 large to show Brownian movement. 



J_J 



Fig. 3. 



Sciile- 'iKovjLsatid.ttis ap\t\ inch.. 



-Liquid inclusions obtained in glass by heating a sealed tube 

 containing water beyond the critical temperature. 



PS. —Since writing the above I have repeated the experiment 

 with similar success, and on this occasion some of the numerous 

 inclusions show Brownian movement of the enclosed bubble. 

 — C. E. B. 



The Igneous Complex of Y Foel Fras, Caernarvonshire. 



By Norman L. Silvester, B.Sc, F.R.Met.Soc. 



THE area under consideration is a portion of the mountain massif 

 bounded on the east by the Conway River, on the north by the 

 narrow coastal plain between Conway and Bangor, and on the west 

 and south by the popular tourist route through Nant.-Francon 

 pass by Llyn Ogwen and down the Afon Llugwy to Bettws y coed. 



