19 



SCHLOESING'S METHOD FOR THE MECHANICAL DETERMINATION OF 



CLAY. 



The method adopted by Schloesing for the mechanical determination 

 of clay is as follows : Knead in a porcelain dish 5 to 10 grams of the soil, 

 previously separated from the gravel arid organic matter, with a little 

 water into a firm paste ; fill the dish half full of water, and rub the mass 

 with the lorefinger; decant without carrying over the sand; repeat the 

 washing by decantation until the sand yields nothing further to the 

 water. All the waters of decantation are collected together, inaidug a 

 volume of 300 to 400 cubic centimeters of liquid ; this is treated with 

 nitric acid in small quantities at a time until the solution is acid to test 

 paper. This treatment, has the effect of coagulating the clay and thus 

 clearing up the muddy liquid. The solution is transferred to a filter and 

 the mixture of fine sand and clay washed thoroughly with water until the 

 liquid goes through cloudy; when the contents of the filter are washed 

 with dilute ammonia into ajar of 2 liters' capacity, using about 150 c. c. 

 of the dilute ammonia for this purpose; then fill up the jar with pure 

 water, and let it digest for an hour, agitating it frequently. Set it 

 aside for twenty-four hjurs, and then siphon off the clayey liquid ; 

 the sand resting at the bottom of the vessel is dried and weighed in a 

 dish. This is the fine sand that is ordinarily mixed upin the clay. Its 

 weight deducted from that of the quantity of soil used will give the 

 clay. (Peligot, p. 153.) 



THE EFFECT OF VARIOUS PROPORTIONS OF SAND IN THE SOIL. 



According to Thaer (Peligot, p. 158), when the sand and clay are of 

 equal parts, or in the proportion of 40 of sand to 60 of clay, comprising 

 under this name the finest sand, &c., as found in mechanical analysis, 

 the soil is fitted for all kinds of crops ; with more than CO per cent, of 

 sand they are suitable to rye and barley, rarely for wheat; with 70 per 

 cent, of sand, the soil is suitable still for the cultivation of barley, and 

 especially for the cultivation of rye ; it is easily worked, but the manures 

 are rapidly used up; with 90 per cent, of sand, the soil becomes dusty 

 in dry weather, and it becomes difficult to reap any benefit from it. 

 With less than 30 per cent, of sand, the very clayey soils are still fitted 

 for the cultivation of oats. When the proportion of sand is 30 per cent, 

 the barley raised is better than the wheat. 



THE CHEMICAL PROPERTIES OF SOIL. 



A knowledge of the chemical composition of a soil is often of great 

 benefit to the farmer, as allowing him to judge whether it contains the 

 proper soil-constituents of which the crop he proposes to raise stands in 

 need, or, being deficient, what is likely to prove the best fertilizer to be 

 applied. Mere analytical results do not, in a great many cases, show 

 the agricultural capabilities of a soil; thus, there are many soils whose 



