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Analysis of the GU-i-toorsch, or Sour Clay, used in acidulating^ 

 Sherbet, in Persia, By Edwaed Tuener, M. D. F. R. S. E. 

 Professor of Chemistry in the University of London. Com- 

 municated by the Author. 



V-lUR intelligent young friend, and former pupil, Lieute- 

 nant Alexander, in his lately published Travels from India 

 to England, a work highly creditable to him as a writer and 

 observer, says, " The road to Dalkec is exceedingly stony; 

 and, at eight miles from it, is a capital sporting tract, with a 

 date jungle and swamp on the left. We were here assailed by an 

 insufferable sulphureous effluvium, shortly after we crossed, from 

 several naphtha and sulphureous streams, which issued from the 

 hills, round the bases of which the road winds. At the fountain 

 head the water is lukewarm. The streams have, on their mar- 

 gin, a whitish-grey earth, which is of an acid and saltish taste ; 

 it is termed Gil-i-toorscJt, or Sour Clay. The taste is probably 

 occasioned by a mixture of alum and sal ammoniac. It is used 

 in acidulating sherbet. I brought away a small quantity of this 

 substance for my esteemed preceptor Professor Jameson *.''' 



Some time ago, the specimen of gil-i-toorsch was sent to me 

 by Lieutenant Alexander. I requested my friend Dr Turner to 

 analyze it, and the following is the Doctor''s report : — " The gil-i- 

 toorsh consists partly of a coarse earthy powder, and partly of ir- 

 regular grains, of about the size of a pea. The interior of the lat- 

 ter is of a white colour, as described by Mr Alexander, but the 

 surface of the particles is brown. This colour is owing to iron ; 

 for the earth has been kept in a vessel of tinned iron, which is 

 strongly corroded. The earth is slightly moist, and has a sour 

 and inky taste. With distilled water, it yields a solution con- 

 taining a considerable quantity of free sulphuric acid and suL 

 phate of iron. With nitrate of silver, it gives scarcely a trace of 

 muriatic acid, and it is almost equally free from alumina. It 

 does not, therefore, contain either sal ammoniac or alum. By 

 the action of pure potash, a trace of ammonia was detected. The 

 earthy matter contains some silica ; but its chief constituent, es- 

 pecially of the larger grains, is sulphate of lime, some of which 



• Travels from India to England, comprehending a visit to the Birman 

 empire, by James E. Alexander, Lieutenant in his Majesty's 13th Light Dra- 

 goons. 4to. Parry & Allen, London 1827. 



