] 22 VARIOUS KINDS OF MANURE. 



the formation of tanks for their reception has been strongly recom- 

 mended, in which the ammonia is fixed by the addition of sulphuric 

 acid or charcoal They can be applied after vegetation has advanced, 

 and they are in a state to be made at once available to the crop. More 

 recently some have advocated a system of steeping seeds and grains in 

 certain solutions before sowing them. Professor Johnston suggests 

 a mixture of phosphate of soda, sulphate of magnesia, nitrate of potash, 

 common salt, and sulphate of ammonia (1 Ib. of each), in ten gallons 

 of water, to steep 300 Ibs. of seeds, which are to be afterwards dried 

 with gypsum or quicklime. 



249. The following experiment, conducted by Mr. Wilson, at Knock, 

 near Largs, shows the mode of estimating the effects of manures. The 

 land was a piece of three-year old pasture, of uniform quality. It was 

 divided into ten lots, and these were treated with different kinds of 

 manure. The quantity of well-made hay is given in Ibs. : 



Produce Rate 

 per Lot per Acre, 



Lot 1 .Left untouched 420 3360 



2. 2 barrels Irish quicklime ... 602 4816 



3 20" cwt. Lime of pas-works, 651 5208 



4. 4| cwt. Wood charcoal powder, 665 5320 



52 bushels Bone-dust 893 5544 



618 Ibs. Nitrate of potash, 742 5936 



720 Ibs. Nitrate of soda, 784 6272 



8 2 1 bolls Soot, 819 6552 



9 28" Ibs. Sulphate of ammonia 874 6776 



10. 100 gallons Ammoniacal liquor of gas-works. \ Q 



5 Tweddell's hydrometer,.../ 



The value of each application was the same, all were applied at the 

 same time, and the grass also was cut at the same time. 



250. Plants are thus employed to form from the atmosphere and 

 soil those organic products which are requisite for the nourishment of 

 man and animals. While an animal consumes carbon so as to form 

 carbonic acid, gives off ammonia in various excretions, transforms 

 organized into mineral matters, and restores its elements to air and 

 earth ; a plant, on the other hand, fixes carbon in its substance and 

 gives off oxygen, forms from ammonia solid compounds, transforms 

 mineral into organized matters, and derives its elements from the air 

 and earth. Thus, says Dumas, what the atmosphere and soil yield to 

 plants, plants yield to animals, and animals return to the air and earth, 

 a constant round in which matter merely changes its place and form.* 



* For fuller particulars as to the food of plants, analyses of plants, soils, manures, and rota- 

 tion of crops, see Johnston's Lectures on Agricultural Chemistry; Liebig's Works; Dumas on 

 Organic Nature; Davy's Agricultural Chemistry, by Shier; Mulder's Chemistry of Organic 

 Bodies, translated by Fromberg ; and various Papers in the Quarterly Journal of Agriculture 

 1844-46 ; Saussure's Works ; Daubeny on Rotation of Crops, Phil Trans. 1845 ; Boussingault, 

 Economic Rurale. 



