84 Mr Sharpe on the Foliation and Cleavage of 



The destruction of the floor of the oil store-room, and the over- 

 turning, in consequence, of the oil-tanks and combustibles into the 

 well of the boiler-room, was probably the crisis of the fire. A mass 

 of combustible vapour would speedily be generated, and shot about 

 on all sides, of which the kindling power upon the new and painted 

 timber of the bulkheads and decks would be wholly irresistible. 



The burning of the Amazon impresses most emphatically the 

 dangerous and uncontrollable character of a fire arising in the engine 

 or boiler-room, where the combustion is animated by a steady and 

 powerful circulation of air, and the danger of collecting combustible 

 matter together in such a place. The removal of the oil stores to a 

 safer locality is, fortunately, generally practicable, and is the measure 

 best calculated to prevent the recurrence of any similar catastrophe. 

 I have the honour to remain, Sir, &c. 



Thos. Graham. 



To the Lords of the Committee of 

 Privy Council for Trade. 



— The Quarterly Journal of the Chemical Society, No. xvii., 

 p. 34. 



On the Foliation and Cleavage of Bocks of the North of Scot- 

 land. By Daniel Sharpe, Esq., F.R.S., V.P.S.G. 



Mr Sharpe, in a paper read to the Royal Society of Lon- 

 don on the 15th January 1852, applies the term, cleavage or 

 lamination, to the divisional planes by which stratified rocks 

 are split into parallel sheets, independently of the stratifica- 

 tion ; foliation, to the division of crystalline rocks into layers 

 of different mineral substances ; slate, to stratified rocks in- 

 tersected by cleavage ; and schist, to foliated rocks only 

 which exhibit no bedding, independent of the foliation. 



He considers that no distinct line can be drawn between 

 gneiss and mica schist, chlorite schist, &c, which pass from 

 one into the other by insensible gradations ; have the same 

 geological relations, and foliation subject to the same laws. 

 He states that their boundaries have been laid down arbi- 

 trarily on the published maps of Scotland. The quartz rock 

 of MacCulloch includes two formations ; the one a quartzose 

 variety of gneiss, included in this paper under that head ; 

 the other, a stratified sandstone altered by plutonic action. 



The author treats the foliation of gneiss and schist as a 



