193 
church is spoken of, which seems to have consisted in an enlarge- 
ment of the choir of the previous church, so that the date of foun- 
dation and addition would be 1150 and 1250.” 
The glass from Dunfermline Cathedral was given me by the sex- 
ton, as having fallen from the windows, and had been long in his 
possession. — G. W. 
The specimens of glass submitted to investigation were six in 
number, namely, four window-glasses, one bottle-glass, and one 
basalt-glass. 
1. Window-glass from Dumbartonshire. 
2. Fragments from a window in Dunfermline Abbey. 
3 and 4. Fragments of window-glass from Dunblane Cathedral. 
5. A bottle from the laboratory of Dr Joseph Black. 
6. Basalt-glass, manufactured by the Messrs Chance and Co. 
Where the quantity of material was sufficient, the following points 
were determined with each specimen. 
1° Specific gravity. 
2° Solubility in water. 
3° Solubility in alkalies. 
4° Solubility in acids. 
5° Quantitative composition. 
The method of examination was that employed by most chemists 
for the analysis of silicates, namely, fusing the substance with car- 
bonate of potash and soda, dissolving the fused mass in acid, and 
estimating the substances in solution. The solvent action of water, 
acids, and alkalies was ascertained by subjecting the specimen, in 
fine powder, to each of these menstrua, for some days, and in most 
cases analysing the liquid containing the soluble part of the glass, 
The specific gravity was determined in the usual manner practised 
in the laboratory, a mean number being deduced from the results of 
three experiments. 
Dumbartonshire window glass had a specific gravity of 2*55. 
Water dissolved substances from it to the amount of *14 of a 
grain per cent., consisting mainly of silica, together with lime, iron, 
alumina, magnesia, and soda in smaller quantities. 
Potash dissolved the glass to the extent of *76 of a grain per cent. 
The quantitative composition of Dumbartonshire glass is the fol- 
