192 Bibliography. 
“The amount of vegetable matter soluble in a solution of ar or 
ate of ammonia, is 1.25 grains, and a solution of carbonate of potash F) 
takes up 1.8 grains. ee 
“The vegetable soluble matters analyzed, were ascertained t be ‘ 
the crenic and apocrenic acids, with a little crenate of lime.” 20m 
We would add, that the method by which this analysis was per- 
formed, seems defective in not testing for the presence of carbonic 
acid in the soil before heating to full redness, whereby, in Htprtte- 
bility, the carbonic acid is expelled ; for we have since obtained sat- 
isfactory proof of the existence of carbonic acid in the Nile soil.* 
This soil was judged to contain no potassa on the evidence yielded 
by the trial prescribed in the present plan of analysis, (by diges- 
tion with nitric acid and deflagration with charcoal.) But Professor 
Mitscherlich has shown that the existence of potassa in aluminous 
soils may be much more satisfactorily proved by digesting them with 
sulphuric acid, when if any potash is present alum will be found. 
We accordingly digested 200 grains of Nile soil in dilute sulphuric 
acid, filtered it, and evaporated the solution to entire dryness, redis- 
solved in distilled water, and on concentrating the solution, (which 
had a very strong taste of alum,) obtained distinct crystals of sul- 
phate of alumina and potassa. This result is-satisfactory, inasmuch 
as it makes the analysis coincide more nearly with those which have 
been before published from the same country, all of which represent 
the soil as containing potash. : e : 
The method pursued in estimating the organic constituents of soils, 
was different from that which has been generally followed in similar 
cases, and entitled to much confidence. So far as we are informed, Dr. 
Jackson is the first who has proved by reiterated trials, that the so 
called humus, geine, apotheme, &c. of previous authors, is mainly 
composed of two acids, first discovered by Berzeliust in the waters of 
Porla Well, in Sweden, and called by him (from #9777, @ fountain) 
erenic and apoerenic acids. They communicate to that water a bitter 
taste and slightly brown color, and have been fully described by him 
in the memoir before the Stockholm Academy in 1833, before cited. 
We cannot here give any account of the properties of these acids; 
nor is it necessary, since their history may be found detailed in the 
standard works. (See Thomson’s Chemistry of Organic Bodies: 
Vegetables, 1838, p. 153 et seq.) . 7a 
Whoever will read with attention the profound work of M. Liebig, 
noticed in this number, will feel, if his conclusions are to become the 
* Consequently the 2.02 of phosphate of lime in the above analysis, would pro 
bably be nearer the truth if it read carbonate instead of phosphate of lime. 
17 : 
t-B.c 
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