54 



Essay on the Analysis of Soils. 



these will be found mixed with the coarser earths separated 

 by the sifting : not being a part of the natural soil^ they need 

 not be taken into the account ; but they may be separated 

 by washing the earths, as they are much lighter, and will come 

 over in the first decantations. They may be dried and weighed, 

 and the quantity set down in the result, if it is desirable. 



Some very barren sands, containing very little argillaceous 

 earth or humus, may readily be known by the copious sandy 

 deposit which they rapidly make when diffused through water. 

 Good natural loams are not so easily judged of; but the pre- 

 ceding mode of analysis will in general detect their intrinsic value. 

 When a soil contains peaty matter, it is easily discovered by the 

 irregular black particles which are visible in it. Peat differs from 

 humus only in being in a different state of decomposition, and 

 containing a considerable portion of tannin ; when acted upon by 

 lime or alkalies, and brought into a state of greater decomposi- 

 tion, it is not to be distinguished from humus in its qualities. 



The only instruments absolutely required for the foregoing 

 analysis are, in the first place, two good balances, one capable of 

 weighing a pound and turning with a grain, and one weighing 

 two ounces and turning with the tenth part of a grain. * Next^ 

 the combination of sieves, which we have described, and which 

 may easily be made by any tin-smith. But any sieves of the 

 required fineness, whether of metal, horse-hair, or silk, provided 

 they be of the proper texture, will answer the purpose for a 

 trial. Some earthen or glass jugs, and two or three glass tubes^ 

 18 inches long, open at both ends, which may be obtained at any 

 glass-blower's, or chemist's, a glass- funnel, and some filtering 

 paper will complete the apparatus. The only chemical sub- 

 stance indispensable to the analysis, is some muriatic acid, com- 

 monly called spirit of salt. A little test-paper to detect acids in 

 the water with which the soil has been washed, and an infusion 

 of gall-nuts to ascertain the presence of iron, may be useful. A 

 small glass-phial will serve for the specific gravities. The whole 

 of these instruments and materials may be procured for a very 

 small sum. If the foregoing process is carefully followed, any 

 person, however unaccustomed to chemical operations, will soon 

 be enabled to satisfy himself as to the composition of any soil of 

 which he desires to know the comparative value. He must not 

 be disheartened by a few failures at first. However simple every 

 operation may appear^ it requires a little practice and much pa- 



* If there is a doubt of the accuracy of a balance, the best mode of weigh- 

 ing is to poise the substance to be weighed with fine sand, and then substi- 

 tute weights for it, till the sand is poised again. If a certain portion is to 

 be weighed, poise the given weight with sand ; then remove the weight, 

 and poise the sand with the substance to be weighed. 



