190 Bibliography. 



oxalate of lime into carbonate ; note its weight. 6, Add to the am- 

 moniacal solution (4) from which the lime has been thrown down, 

 phosphate of soda — if any precipitate occurs it will be magnesia, in 

 the state of bi-phosphate, 40 per cent, of which may be set down as 

 magnesia. 7. Now lastly run a current of sulphuretted hydrogen 

 through the remaining solution ; if manganese is present it will fall, 

 and may be reduced to black oxide. 



In order to ascertain the existence of alkaline salts, burn off the 

 vegetable matter from another 100 grains, and digest in a little nitric 

 acid ; dilute and filter, and evaporate to entire dryness ; fuse the re- 

 sulting salts and add a trifle of prepared charcoal — if any nitrates are 

 present, deflagration will ensue, and the alkaline bases will be con- 

 verted into carbonates.* Such is the method pursued in the analysis 

 of the inorganic constituents of the soil; and we can, from having 

 personally spent several weeks in Dr. Jackson's laboratory, confi- 

 dently assert, that no labor or pains was spared in carrying it out in 

 every detail, both on the part of himself and his assistants. 



As an example elucidating the foregoing, we quote — " The follow- 

 ing analysis of the rich alluvium of the Nile in Egypt, a soil cele- 

 brated from the remotest antiquity for its luxuriant vegetation, will 

 serve as a good example. The analysis was made in my laboratory, 

 and under ray supervision, by my highly esteemed friend, Benjamin 

 Silliman, Jr., who received the soil from Rev. George Jones, U. S. N., 

 who took it himself during a visit to Egypt in 1835. I shall give the 

 process of analysis, as an example of our methods. 



"The soil consisted of the annual layers deposited by the Nile du- 

 ring its periodical overflowings. It contained some fine particles of 

 mica, deposited between its layers, but was destitute of any pebbles 

 or sand. It is of a deep brownish yellow color, and splits readily 

 into thin leaves when dry. The soil having been crushed fine, was 

 sifted through a gauze sieve, and no sticks or fragments of rocks were 

 found, excepting the fine particles of mica above mentioned. One 

 hundred grains of the soil dried at 300° F., lost 7.05 grains, which 

 was water. 



"Its vegetable matter was then burned out in the platina crucible, 

 placed in a red hot muffle, and the loss was 6.9 grains, which was 

 vegetable matter. Digested in muriatic acid 23.432 grains were dis- 

 solved, and 68.7 consisted of the insoluble silicates. The analysis 

 having been at this stage lost by accident, was renewed, and 100 

 grains of the soil previously dried at a temperature above that of boil- 



* It will be seen by reference to the analysis of the Nile soil that tliis method 

 is not always conclusive, and we cannot doubt if Dr. Jackson had practiced the 

 method of Mitscherlich, he would have found more proofs of the existence of 

 potash in the soils of Rhode Island than he has given them credit for. 



