ANALYSIS OF A PECULIAR SOIL. 183 



several hours, in a silver crvicihle upon heated iron. It rr 

 142*8 gvifuis, equivalent to Q-S '8 ©f muriatic acid. 



The 13'S t^rains precipitated bj'- ammonia were boiled to 

 dryness in a ley containing 20 grains of potash; and the 

 matter remaining in the silver crucible, whicli had resisted 

 the action of the potash, after exposure to a low red heat, 

 ~ 8 jjniins. 



What the potash had dissolved was separated by muriate Alumlne. 

 of ammonia from its solvent. .It was alumina^ and must 

 have amounted to 5*8 grains. The 8 grains of residuum 

 ^bove mentioned became, by ignition, of a dark brown colour. 

 Sulphuric- acid did not apparently net upon it, until a small 

 piece of sugar had been added. The sulphuric solution 

 was decomposed by perfectly saturated carbonate of am- 

 monia added to excess. After the precipitate thereby 

 produced had been separated by the filter, and sufficiently 

 edulcorated, phosphate of soda separated from the clear 

 fluid the tiiple salt of magnesia first noticed by Dr. VVol- 

 laston. it — 3*9 grains, which, according to the calcula- 

 tion contained in Dr. Marcet's very inge-nious and scientific 

 analysis of the Brighton waters, indicate 0*74 of magnesia, 

 which reduces the remaining substance to 7 "-6 grains. It 

 had all the properties of manganese. What proportion of Manganese, 

 acid the muriates of alumina and manganese respectively 

 contain, has not, I believe, been accurately ascertained. 



I should not have considered the facts above detailed as A^lmilar soil 



, ob-erved seva- 

 l)eing worthy of record, if I had not coupled them with ral ytarsa|;cx, 



the recollection, that, several years ago, I had examined a 

 soil, which I have reason to think contained predse-y the 

 same saline iubstances as the subject of this letter. Muriate 

 of alumina is not, indeed, mentioned in my notes upon it, 

 out the results of the experiments which 1 then ujade agree 

 so exactly with what I have recently observed, that I hiive 

 not the least doubt, that muriate of alumina was present 

 also, with the other salts. 1 did not then detect it, as' iu 

 the then state of chemical means, it was not so easily disco- 

 verable. That soil contained also a free acid, and the muJ 

 riate of manganese, with the other suits, which I have be- 

 fore enumcriited. It differed, in one respect, from ffiat 

 which I lately examined: in haying a much larger quantity 

 of vegetable extractive matter mixed With it**" Tile *^pot 



where 



