476 Reviews — Materials required in Glass-making. 



(Argyllshire), Portsoy (Banff), and Monymusk (Aberdeenshire) ; 

 near Belleek, on the borders of co. Donegal and co. Fermanagh, in 

 the Glenties area of co. Donegal, and the BellmuUet area of co. 

 Mayo. 



Felspars of the best qualitj'- (grade 1) occur in Cornwall at 

 Tresayes, Kernick, and Trelavour, and in the neighbourhood of Belleek 

 in Ireland. These occurrences are all situated fairly near to road, 

 railway, and the sea, but the quantity in each case is limited. 

 Each area yields hand-picked material suitable for the best glass and 

 pottery work, showing from 10 to 13 per cent K2O, but none of 

 them can be worked on the large scale for the extraction of potash. 



Bound Rhiconich and near Durness in Sutherland, on Erris Head 

 near BellmuUet, and on the Gweebarra Biver in co. Donegal there are 

 millions of tons of pegmatite of grades 2 and 3. These, however, 

 would not yield more than 8 or 9 per cent of potash after hand- 

 picking, and are almost unworkable on account of their inaccessibility. 

 These large deposits might possibly be worked for the extraction of 

 their potash, but the operations would have to be conducted on very 

 efficient lines for such a project to be payable, the chief difficulty 

 being the shipping of the felspar, on account of the distance of the 

 deposits from available harbours. 



The supplies of highi-grade spar in the Cornish and Belleek areas 

 might be sufficient for the requirements of our industry for a limited 

 time, but not for any considerable period, owing to the small reserves 

 available. Certain felsites near Wicklow and Waterford and some 

 Cretaceous glauconitic sands have been suggested as sources of 

 potash, but unfortunately their potash content is in most cases much 

 too low and never sufficiently high to render them worth working. 



The paper is furnished with numerous analyses of the felspars and 

 pegmatites, including some foreign as well as the British examples. 

 It represents a very considerable amount of work, since the author 

 has visited all the localities which he describes, some of which, being 

 situated in the wildest parts of north-west Scotland and the west of 

 Ireland, are very difficult of access. 



W. H. W. 



Y. — British Besoueces of Sands and Bocks used in Glass-making.' 

 By Professor P. G H. Boswell. Second and complete edition, 

 pp. xi -j- 170, with 10 plates and 13 figures in the text. 

 London: Longmans, Green & Co. 1918. 



N this second edition the author's two earlier memoirs on British 

 glass sands are combined into one volume. A few parts have 

 been rewritten and some further information has been added, but 

 otherwise most of the matter is the same. The book in its present 

 form is a comprehensive survey, not only of British glass sands, but 

 of the more important foreign occurrences, and also of other deposits 

 essential to the glass industry, such as those of potash and alumina. 



W. H. W. 

 ^ See also Geol. Mag., March, 1918, p. 131. 



