ABSORPTIVE rOWER OF TURF. 107 



plants from their solutions, and pli^^sically fixing them ; 

 but they have not, in the moist state, that soft, plastic, 

 and yielding condition of the clay in arable soil, which 

 permits the intimate contact of the roots with the earthy 

 particles. The best substitute for the purpose is coarsely- 

 powdered turf, which, in the moist state, forms a plastic 

 mass, bearing a remote resemblance to clay, and, like 

 arable soil, absorbs all elements of the food of plants from 

 their solutions, x^ccordingiy, Nligeli and Zoeller used in 

 their experiments coarsely-powdered turf as the vehicle 

 of the nutritive substances, after having ascertained its 

 absorptive power for the several elements of food. 



A litre (1-76 pint) of turf, weighing 324 grammes 

 (4987-6 grs.), was found to absorb from solutions of 

 carbonate of potash, carbonate of ammonia, carbonate of 

 soda, and phosphate of lime — 1-45 grammes (22-4 grs.) 

 of potash, 1-227 grammes (19 grs.) of ammonia, 0-205 

 gramme (3-2 grs.) of soda, and 0-890 gramme (13-7 grs.) 

 of phosphate of lime equal to 0-410 gramme (6*3 grs.) 

 of phosphoric acid. 



The quantities of potash and ammonia here given do 

 not show the total amounts of these substances which the 

 turf will absorb to the point of complete saturation, but 

 merely what it will take up when simply mixed with the 

 solutions, and left in contact with them for a few hours. 

 K we add more of these solutions to the turf-powder, the 

 fluid exhibits an alkaline reaction, which disappears again 

 after one or more days ; and it is only at the end of 

 eight days, w^hen the litre (1-76 pint) of turf has taken 

 up 7-892 grammes (121*6 grs.) of potash and 4-169 

 grammes (64-2 grs.) of ammonia, that the alkaline re- 

 action remains permanent. What we shall hereafter 

 designate as saturated turf contains only i of the potash 

 and ^ of the ammonia, which v/ould be absorbed by that 

 substance to the point of complete saturation. 



