FOOTNOTES:
[1] A quarter is equal to six bushels, and the average produce in wheat and rye 18 bushels per acre. For the whole kingdom the deficit is 2,820,000 quarters. See Geographic Mathematic, art. Great Britain.
[2] See the introduction to Dickson's Practical Agriculture, 2d vol. quarto.
[3] Marshal, vol. iv. p. 575.
[4] Dickson's Practical Agriculture.
[5] Idem.
[6] Young's Tour through Ireland, vol. ii. p. 302.
[7] Mr. Hume quotes with approbation an author, who complains of the decay of tillage in the reign of Elizabeth, and who ascribes it to the increase of pasturage, in consequence of the restraints imposed on the exportation of grain, while that of butter, cheese, &c. was free. The history of Europe, if read with an eye to public economy, furnishes an abundant proof, that the greatest obstructions to agriculture have arisen from the interference of government. We have here no sly allusion to our own projects of a state board of agriculture, of a chymico agricultural professorship, nor even of an agricultural college, if the treasury in its wealth, and the legislature in its wisdom, should deem such institutions useful or necessary.
[8] See Gisbert's experiments on pure earths and their mixtures. See also Davy's Elements of Agricultural Chemistry, p. 156.
[9] In this respect nature has been neither negligent or niggardly, if (as Fourcroy asserts) the purest sand be a mixture of quartz, alumina, and sometimes of calcareous matter. Speculative geology is romance, and does not merit the name of science; yet is science obliged to borrow her theory of soils. The alternation of heat and cold, moisture and dryness, decomposed the mountains of primitive, secondary and tertiary formation; rains, and the laws of gravity, brought these from places of more, to places of less elevation—where, by mechanical mixture and chymical combination, the present substrata were formed. But these were yet naked and unproductive, when the Cryptogamia family (mopes and lichens) took possession of them, and in due time produced that vegetable matter, which made the earth productive and the globe habitable!
[10] Dead animal and vegetable matter, in the last stage of decomposition, give a black or brown powder, which the French chymists call terreau or humus, and which Mr. Davy calls an extractive matter; this is the fertilizing principle of soils and manures.
[11] The opinion is general among the chymists of Europe, that magnesian earth is not only barren itself, but the cause of barrenness in other soils in which it may abound, unless saturated with carbonic acid. See Base, Tennant, and Davy.
[12] Davy says this never exceeds one fiftieth of the whole product.
[13] Shæder maintains the doctrine, that the earths found in plants are created there by the process of vegetation. His essay on this subject was crowned by the academy of Berlin, in 1801. His experiments were the first to determine the different quantities of silica found in different kinds of grain.
[14] Moisten a bean in warm water, and detach the skin that covers it, and it readily divides into two parts; these are called lobes.
[15] Bonnet's experiments show, that it is the under surface of the leaf that performs this function, The upper surface has a different office.