320 [Dec. 1845. 



The undissolved residuum filtered, washed, and ignited weighing 63.55 

 grains. It is a powder of a lighter grey than the original soil. Minute par- 

 ticles of white quartz, and some with a reddish tint are discernible by the 

 help of a lens. 



7. The solution filtered from the above residuum was treated with sulphydric 

 acid, to ascertain whether lead, copper, mercury, tin, antimony, or arsenic, 

 existed in the soil. A reddish white tint, indicative of a bare trace of anti- 

 mony, was all which could be procured. The liquid smelling strongly of sul- 

 phydric acid, the sulphur was separated, and then the solution was neutral- 

 ized with pure ammonia. 



8. Sulphydrate of ammonia was added, throwing down a copious precipa- 

 tate of sulphuret of iron and alumina, which was filtered out, redissolved in 

 chlorhydric acid, with a little nitric, and boiled to peroxidize the iron; the 

 solution was then precipitated and boiled with pure potash, separating the 

 iron, which being ignited, weighed in the state of peroxide 8.07 grains. 



9. Having acidulated the potash liquid, it was precipitated by ammonia 

 and gave of ignited alumina 2.64 grains. 



10. The solution, filtered from the sulphurets, was concentrated, treated 

 with chlorhydric acid, the precipitated sulphur separated, and after neutral- 

 izing by ammonia, was precipitated with oxalate of ammonia, allowed to re- 

 pose 18 hours, then heated and filtered. The oxalate of lime thus obtained, 

 was, after ignition, repeatedly moistened with a solution of carbonate of am- 

 monia, and re-ignited till it ceased to gain weight. The carbonate of lime 

 was 12.6 grains. 



11. Ammonio-phosphate of soda applied to the liquid filtered from the oxa- 

 late of lime, after the same had been duly concentrated, entirely cooled and 

 neutralized by pure ammonia, threw down ammonio-phosphate of magnesia, 

 which, separated and ignited, gave of phosphate of magnesia, 5.15 grains, equal 

 to 2.06 grains of magnesia, or 4.25 of its carbonate. 



From the preceding operations we obtain the following composition of this 



soil, viz : 



per cent. 



Water obtained at 212°, - - - 4.20 



Organic matter soluble in boiling water, ... 2.30 



Insoluble organic matter, ... . 2.15 



Peroxide of iron, ------ 8.07 



Alumina, • - - - - - - 2 - 6 * 



Carbonic acid, ------ 5.55 



Magnesia, ...... 2.06 



Lime, „ . - - - - 7.11 



Insoluble silicates, ..... 63.55 



Loss, - 2.37 



100. 



