TJie Vitrified Cement from an ancient fort. 185 



On the Vitrified Cement from an ancient fort. By 

 G. H. Bailey, D.Sc, Ph.D. 



{Received March ^th, i88g.) 



In October, 1882, Dr. Angus Smith described before 

 this Society a vitrified mass of stone from Glen Nevis, and 

 gave an analysis of the stone. 



In the Manchester Museum at the Owens College is 

 also a mass composed of fragments of gneiss cemented 

 together by vitrefaction and said to be derived from the 

 forts of the Picts. 



Having recently visited some of these forts in the High- 

 lands, I was interested in this specimen, and having, by the 

 permission of Professor Boyd Dawkins, obtained a sample 

 of the stone, I asked one of my students, Mr. W. B. Hopkins^ 

 to make an analysis of the vitrified part. The points of 

 interest seemed to me to be : — 



{a) Whether the materials which had been converted 

 into the molten mass had been selected by trial in order that 

 a body of low fusing point might be obtained or had been 

 taken indiscriminately ; 



{b) whence they were derived ; 



{c) what temperature would be required in order to bring 

 about the fusion ? 



The vitrified part showed locally a glazing, and had 

 been distinctly fluid, but now presented somewhat the 

 appearance of lava, being honeycombed with air spaces 

 from which gases had apparently escaped during the fusion. 

 Samples were taken from different parts and mixed together, 

 and partial examination was made of the different samples 

 with a view to detecting variations in the composition of 



