[.143 ] 



XVIII. 



SLATES AND CLAYS OF IEELAND (BRICKS, Etc.). By G. 

 H. KINAHAN, M. R. I. A. WITH INTKODUCTION AND 

 BUILDING NOTES by R, CLARK. 



[Read January 18, 1888.] 



Part II. — The Clays of Ireland (Bricks, Etc.). 



The Irish Clays to which attention will be directed are : Alumite, 

 or Alum Clay : Diatomite, or Diatomaceous Clay ; Fire-day, Porce- 

 lain, or China-clay ; Fuller'' s Earth, Pipe, Potter's, and Brick-clays. 



The Alumite occurs as a subordinate in the Tertiary Iron- 

 measures, Co. Antrim ; it is used in the manufacture of alum, 

 &c. (vol. v., p. 251). 



Diatomite 1 , when of good quality, is nearly pure silica, being 

 made up solely of diatoms ; it is now used in the manufacture of dy- 

 namite to mix with the nitro-glycerine. It usually occurs as an accu- 

 mulation under, or associated with, peat, in bowl- or saucer-shaped 

 hollows. Lately it has been discovered in a number of places in 

 North Scotland, but as yet, in Ireland, it has only been found in 

 the valley of the Bann, Cos. Londonderry and Antrim (page 147). 

 Fire-clay is recorded in the different coal-fields and tracts of coal- 

 measures. In the Co. Tyrone {Coal Island and Annaghone) it occurs 

 in quantity, and of excellent quality (page 164). In the Leinster 

 coal-fields, also, as pointed out years ago by Griffith, it is plentiful 

 and good ; but for some unknown reasons it never appears to have 

 been utilized. In the Connaught coal-fields, where the quantity 

 is less and the quality inferior, it was for a short time manu- 

 factured into bricks and other fire-ware ; but there are no records 



1 Note added in the Press. — More recently, on account of the quantity of silicia 

 it contains, it has been proposed to be used in the manufacture of fire-resisting cases 

 for metal pipes, &c, specimens of which are exhibited in Glasgow at the present time 

 (June, 1888). 



SCIEN. PKOC. R.D.8. — VOL. VI., PT. III. M 



