374 
Proceedings of the Royal Society of Edinburgh. [Sess. 
XXI.— A Chemical Investigation into the Nature of the Clay- 
Substance in the Glenboig Fireclay. By D. P. M c Donald, 
M.A., B.Sc., Baxter Demonstrator in Geology in the University of 
Glasgow. Communicated by Professor J. W. Gregory. 
(MS. received March 5, 1910. Read March 21, 1910.) 
This investigation into the nature of the clay substance contained in the 
fireclay from Glenboig was undertaken at the suggestion of Professor J. W. 
Gregory. Professor Gregory thought that the fine material might be 
halloysite, and the results obtained tend to confirm this view. 
The very finest material was separated by repeated washing from a 
sample of the best clay, and used for the analyses. Although apparently 
white when suspended in water, the material when dry had a decided buff 
colour. As the colour indicated the presence of some impurity, efforts were 
made by further washing to remove it ; but with no good result. The 
sample was dried in the steam oven and analysed. 
Analysis. 
Si0 2 =46*67 per cent. 
A1 2 0 3 + small 1 
amount of >=37*65 „ ,, 
Fe 2 0 3 ) 
H 2 0 at 105° C. = 2*13 „ „ 
H 2 0 (combined) = 12*66 „ „ 
99Tl 
The analysis showed the presence of CaO and MgO in small amount — 
T6 per cent, of CaO. The MgO was not determined. 
This result agrees with those obtained by Dr C. Fawsitt * — 
I. 
n. 
Si0 2 . . . 
Al 9 O s . . 
h 9 o- \ 
h 2 0+/ • 
48*05 
36*53 
13*45 
46-6 
37-2 
13-85 
98-03 
97*65 
* Proof in causa The Caledonian Railway Company against The Glenboig Union Fire- 
clay Company, Ltd., p. 168. 
