Ashes of Sugar-Canes from the West Indies. 535 



given me by William Gourlie, Jun,, Esq. No. 9, consisting 

 of full-grown canes with but few leaves, from the island of 

 Grenada, was given me by Mungo Campbell, Jun., Esq. 

 No. 10, from Hampden estate, Trelawny, Jamaica, consisted 

 of transparent canes in full blossom, grown about six miles 

 from the sea, and manured with cattle-dung. No. 1 1 consisted 

 also of transparent canes from Ironshore estate, St. James's, 

 Jamaica ; they grew about 200 yards from the sea, and were 

 old rattoons, aKso manured with cattle-dung. No. 12, from 

 Content estate, St. James's, Jamaica, were young transparent 

 canes, grown about three and a half miles from the sea, and 

 manured with cattle-dung, guano and marl. For these last 

 three parcels I am indebted to the kindness of William Stir- 

 ling, Esq. of Kenmure. 



The canes after being carefully cleaned were dried in a 

 stove, then charred on a plate of cast iron, and finally incine- 

 rated in a Hessian crucible at a very moderate heat, so as to 

 prevent the ashes from melting. The method adopted in 

 these analyses was chiefly that of Messrs. Freseniusand Will, 

 except in regard to the phosphoric acid. 



The method of proceeding was as follows: — 



I. A quantity of the ash (1 gramme) was boiled with nitric 

 acid, and the filtered liquor was employed to determine the 

 chlorine with nitrate of silver in the usual way. 



II. Another quantity (about 1*5 gramme), dissolved in 

 muriatic acid, was employed for the determination of the sul- 

 phuric acid. 



III. A third quantity (about 5*0 grammes) was boiled in a 

 silver basin for about an hour with a very concentrated lye of 

 caustic soda, to bring the silica into a soluble state, as the 

 ashes were not completely decomposed by boiling with acids. 

 The alkaline mass was then digested with nitric acid, evapo- 

 rated to dryness, again digested with dihite nitric acid, and 

 filtered. The silica, coal and sand in the insoluble residue 

 were determined in the usual way. .The liquor which passed 

 through the filter was employed for the determination of the 

 phosphoric acid, lime and magnesia. The v,'hole of the liquor 

 was measured in a graduated cylinder. 



a. The sulphuric acid was determined in a portion of the 

 liquor by chloride of barium. 



b. Another measured quantity of the liquor, after being 

 neutralized by ammonia, was precipitated by acetate of lead, 

 and the phosphoric acid it contained determined according to 

 the method given by Berzelius. The precipitate was well- 

 washed with boiling water to free it entirely from chloride of 

 lead, and the sulphate of lead precipitated along with the 

 phosphoric acid was calculated from the quantity of sulphuric 



