AGRICULTURAL CHEMISTRY AND GEOLOGY. 147 



and in good heart, with an exposure to the south, was selected for the experiment, and 

 divided into two equal portions. The manure was applied at the rate of twenty cart-loads 

 per acre. 



The whole field was planted with potatoes ; the seed all of one kind, and planted the first 

 and second week in April. All braided well and showed no difference in growth till the first 

 week in July, when a decided superiority began to manifest itself in the half of the covered 

 yards. The vines on the portion of the field manured from the exposed yards began to decay 

 by the latter end of July, while the other portion of the field still retained its dark-green. 

 The crops were taken up on the 1st to the 4th of October, and, after careful measurement, 

 and weighing of two separate portions in each division, the result was as follows : 



With Uncovered Manure. 



Measurement Tons. Cwt Ibs. 



One acre produced 7 6 8 of potatoes, 



do. do. 7 18 99 do. 



With Covered Manure. 



Measurement. Tons. Cwt. Ibs. 



One acre produced 11 17 56 of potatoes. 



do. do. 11 12 20 do. 



As soon as possible after the potatoes were harvested, the field was plowed and wheat 

 drilled in, at the rate of three bushels per acre. As soon as the weather was suitable in 

 the spring, the whole field got a dressing of three hundredsweight of Peruvian guano per 

 acre. During the winter, very little difference was apparent ; but, shortly after the applica- 

 tion of the guano, the wheat on that portion manured by the covered dung took a decided 

 lead, which it retained all summer. The whole field was cut on the 26th of August, 1851 ; 

 the portion manured by the uncovered dung being at least four days earlier than the other. 

 As before, the two separate portions in each half of the field were measured, cut, and stacked 

 separately. On the 4th of September, each portion was thrashed, the grain carefully 

 measured, and the straw. On account of a wet season, the grain was lighter weight than 

 usual, in Great Britain, per bushel. The result of the experiment was as follows : 



With Uncovered Manure. 



Product in Grain. Weight per bushel. Product in straw. 



Acre. Bushel. Ibs. lb. Stones. Ibs. 



1st 41 19 6U 152 of 22 



2d 42 38 61* 160 of 22 



With Covered Manure. 



Product in Grain. Weight per bushel Product in straw. 

 Acre. Bushel. Ibs. Ibs. Stones. Ibs. 



1st 55 5 61 221 of 22 



2d 53 47 71 210 of 22 



These and similar experiments have satisfied Lord Kinnaird of the advantages to be de- 

 rived from having farm-yard manures put under cover. 



On the value of Gas-lime for Agricultural purposes. 



GAS-LIME differs from ordinary lime only in consequence of having imbibed, during the 

 purification of the gas, sulphuretted hydrogen and more or less ammoniacal salts. In num- 

 berless instances it has been used with great advantage in compost heaps. In the neighbor- 

 hood of Edinburgh it has been extensively employed by some of the most spirited farmers. 

 Formerly it used to be given for the carting away ; but now it is sold at 3d. a ton, and the 

 demand is greater than can well be supplied. Some farmers, who have applied liberal dress- 

 ings, state that the succeeding crops have been better than after the ordinary applications of 

 farm-yard manure ; others affirm that, compared with newly-burned lime, it is, in every 

 respect, superior. In Glasgow, the refuse lime is sold at from 1*. 6d. to Is. Gd, a ton. Some 

 have applied it to red land, like caustic lime ; but it will be found much more profitable 

 to compound it with earth, peat, couch-grass, or other vegetable matters. The ammoniacal 

 water of gas-works, in large cities, is generally used in chemical manufactories for the 

 preparation of commercial ammonia ; but in small works, in country villages, it is often 



