90 



THE FARMER'S MAGAZINE. 



agree with Mr. Caird, when he observes fib., p. 

 400) : " There is probably no root crop grown by 

 the EngUsh farmer which is more under the influ- 

 ence of manure than mangold. To no other green 

 crop can a heavy dose be so safely applied ; and 

 the only question with the grower is, to ascertain 

 the kind of manure which, at the least cost, will 

 produce the greatest effect." And he continues : 

 " Not knowing exactly what might be the most 

 suitable dressing for this crop, I last spring 

 adopted the safe method of applying a mixture of 

 all the best manures, in the following liberal pro- 

 portions — viz. : 



13 cubic yards of good dung 

 2 cwt, of Peruvian guano 

 2 cwt. of superphosphate 

 2 cwt. of nitro-phosphate 

 4 cwt. of common salt 



to each acre of my general crop, on a good loam, 

 in Kent, within ten miles of London ; and the re- 

 sult has been very satisfactory. The produce of 

 one measured acre — probably the best in the field 



— weighed upwards of 40 tons of roots (the yellow 

 globe variety) ; and the whole field has averaged 

 over 30 tons." 



These and other details with regard to the 

 dressings for raangold-wurzel I will again refer to, 

 at a season when such remarks may be more useful 

 to the farmer; and I may before that time have 

 occasion to offer a few remarks upon the novel no- 

 tions which, I find, are entertained by some Suffolk 

 farmers as to the feeding properties of roots and 

 grasses, dressed with certain artificial manures. 

 Our time can hardly be more profitably employed 

 than in this kind of practical researches. They 

 apply to a branch of my readers' arduous profes- 

 sion which, I feel, is likely to become more and 

 more an object of his attention, since it relates to 

 the increased production of animal food — of all the 

 returns of our farms, the most likely to be steadily 

 remunerative, since it is the least subject to the 

 uncertain prices induced by the competition of 

 the farmers of more cheaply cultivated foreign 

 countries. 



THE ACTION OF THE ATMOSPHERE ON THE SOIL. 



The earth we cultivate is not composed of inert pas- 

 sive materials, that merely submit to the mechanical 

 and chemical action of varying temperatures, rains, 

 winds, and gases, but is ever vigorously exercising 

 certain powers of its own, among which is its absorp- 

 tive property. This we find treated of in the third 

 division of Mr. Jamieson's prize essay "On the Action of 

 the Atmospliere upon newly-deepened Soil." As re- 

 gards the absorption of gaseous substances, the quan- 

 tity taken up will depend in a great measure upon the 

 amount of surface with which the body to be absorbed 

 can come in contact. Old Jcthro Tull could only 

 theorize upon the advantages of providing by tillage an 

 " internal superficies" ; saying that " one cvibic foot of 

 earth may contain many thousand square feet of sur- 

 face." Our author here, however, is enabled to illus- 

 trate his propositions by the facts of modern science. 

 Thus " Mitseherlich calculates that a volume of one 

 cubic inch filled with globules not exceeding one ten- 

 millionth of an inch in diameter, but arranged so that 

 lines passing through their centres are mutually per- 

 pendicular or parallel, will present a surface of 218,166 

 square feet ; and he considers that the substance called 

 plantinum black may possibly oflfer a surface of this 

 extent. The cells of charred wood are, on an 

 average, one - 2400th of an inch in diameter, 

 according to the same high authority; and its 

 surface for a cube inch would therefore, by cal- 

 culation, be equal to 100 square feet, supposing the 

 charcoal itself to occupy no space. He however found, 

 by immersing a piece of charcoal in water, that only 

 five-eighths of its entire volume are left available for 



the entrance of gases, which would give a surface of 

 73 square feet." Saussure found that charcoal ab- 

 sorbed thirty-five times its volume of carbonic acid at 

 536 deg. Fahr., and at a pressure of 26'895; and am- 

 moniacal gas is condensed within its pores in a far 

 greater degree. 



" All porous bodies which offer a considerable surface 

 to gases act like charcoal. The humus of the soil, and 

 decayed wood, approach very nearly to charcoal in this 

 property ; decayed oak-wood, according to Liebig, ab- 

 sorbing seventj-two times its volume of ammoniacal 

 gas, ailer having been completely dried in the air- 

 pump .... The property which some bodies, such as 

 silica, possess of condensing the humidity of the air, 

 may authorize us," says Mitseherlich, "to conclude that 

 they are adapted for condensing gases.... It will be 

 seen, therefore, how important a matter, even in this 

 respect alone, it is to work the soil when it is in a suit- 

 able state for crumbling down and pulverizing under 

 the action of the plough or other implement used, and 

 not turn it over in a wet, clammy condition, when it 

 sticks together or glazes over in continuous solid lumps. 

 The disintegrating effect of the frost upon it will be also 

 appreciated." 



Moisture, oxygen, ammonia, and other gases are sucked 

 in more voraciously by humus than by any other in- 

 gredient of the soil ; clay, oxide of iron, and magnesia 

 are also great absorbers, but very much depends upon 

 their state of mechanical div ision. At this point of the 

 essay we meet with one of the few observations parti- 

 cularly relating to " newly-exposed" soil ; and this is 

 only the expression of an opinion held by everybody, 



