ON MANURES. 99 



turbed ground gave not a drop. This is equal to the 

 evaporation per hour from an acre, after the most copi- 

 ous rains. Here let us pause and consider ; we can, it 

 seems, generate water in the soil in a dry time, by stir- 

 ring it with a plough or cultivator ! This proves the 

 correcteess of an observation made by Cobbet, I think, 

 on the cultivation of Indian corn, that the effects of a 

 drought upon it may be prevented by ploughing among 

 it every morning while the dew is on. He thus noticed 

 the fact without understanding the cause. Evening 

 ploughing must be preferable to morning, however, as 

 the roots would have a longer time to absorb the genera- 



induced to make the following abridgement, to be inserted as a note to my com- 

 munication. 



■* J. C. Curran, Esq. M. P., to cleanse his foul grounds without resorting to 

 fallows, planted them with cabbages, in a quincunx form, allowing 4 1-Si feet be- 

 tween each plant ; 2350 were set per acre. The manure, about fourteen tons, 

 was deposited as deep as the plongh could penetrate, drawn by four horses, and 

 the plants set directly above it. The plough and harrow, constructed to work 

 betwixt tlie rows, was constantly emplo3^ed during the summer, and tlie ground, 

 a poor cold clay soil, was as completely freed from weeds as it could have been 

 by a naked fallow. The crop in October was 35 1-2 tons per acre, many of the 

 cabbages weighing 55 pounds each. Astonished at his success, and unable to 

 account for it, he by mere accident met with the Bishop of Llandaff 's experi- 

 ments on evaporation from earth [newly ploughed I presume,] which had re- 

 mained for thirty years without any practical application of it to agriculture. It 

 appeared to him highly probable that the rapid growth after the hoeing of drilled 

 grain, was attributable to the absorption of the evaporation produced from the 

 earth, and was the cause of tlie growth of his cabbages. Accordingly, the fol- 

 lowing year he cultivated cabbages and potatoes in the same manner, with like 

 success. In the mean time, he made constant experiments with glasses con- 

 trived for the purpose, to ascertain the quantity of evaporation from the land, 

 which he found to amount on fresh ploughed land to U50 lbs. per hour on the 

 surface of a statute acre, while on the unbroken no moisture arose from the 

 earth. The evaporation from the ploughed land was found to decrease rapidly 

 after the first and second day, and ceased after five or six days, depending on the 

 wind and sun. These experiments were carried on many months ; after July 

 the evaporation decreased. The evaporation after the most abundant rains was 

 not advanced beyond what the eartli afforded on being fresh turned up. Evap- 

 oration from dung is five times as much as from earth, and is equal on the sur- 

 face of an acre to 5000 lbs. per hour. By making use of dung in its freshest 

 state, he says, the farmer may extend his cropping to one third more land, with 

 the same quantity of manure. He recommends covering it deep. Manure ex- 

 posed on the surface tends to no good. I have omitted liis philosophical infer- 

 ences from these experiments, for they are obviously incorrect. Dr. Dana's 

 theory is more satisfactory. Such facts are imperishable, and cannot fail, soon- 

 er or later to enlighten those for whose benefit they are recorded. More than 

 sixty years have now elapsed since the Bishop of Llandaff" sowed the seed of a 

 great improvement in agriculture, which is now just beginning to vegetate, and 

 attract the attention it deserves. Let then every newly discovered fact in science 

 and art be recorded. It will sooner or later benefit mankind. 



