Notes on Agriculture
[ante–12 May 1818]
see p. 17—note ‡ 1. Putrification not essential to render animal & vegetable substances, nutritious to plants. 2 these two not alike in their putrid state; tho’ both nutritious. The former containing essentially azote or nitrogen, the latter a constituent part of some plants only—this discovery of Bertholet1 to be ranked as the most important of the present century concerning organized matter p. 7. note.2
Roots absorb at the extremities only* which consist of a no. of capilary tubes like a brush. p. 9. A great object is to multiply these extremities: for which moisture, & a due degree of penetrability & resistance in the earth necessary—the cutting the smaller roots multiplies their ramifications, hence the utility of horsehoing (& harrowing wheat for same reason) &c. pruning vegetables similar effect.
(☞ *the proof is drawn from immersing the roots in spirits of wine &. which colors the sap when the mouth of the roots are open—& not when closed—& colors also when an incision is made in the bark—but may not the pores of the bark absorb & filter away the color admitted thro’ mouths at the extremities & the incisions?)
Dews more fertilizing because more putrescent than rain—havg. been less elevated & subtilized & therefore containing more muculage from the earth &ca than rain.
Many Insects found to absorb like plants noxious gazes & contribute to purify atmosphere for animals.
Plants subsist wholly on water & gazes floating in air, or emitted from manures &c.
An experimt. in Holland planted a young tree wd. a few oz. in pure water with sand at bottom to hold it up in gls. & witht. any nourisht but the water—after some years its weight was several hundred pounds.
Tho’ plants grow & exhibit the characteristic qualities (as aromatics. &c) in pure water—yet will not seed, fruit, or even flower well if at all, if roots loose in water according to Bonnet’s5 expemts.—but in moss are bro’t to perfection by watering alone p. 6 (☞ quere. might not the mucilage or other matter belonging to the moss have been dissolved by the water & become food to the plant. A second or more crops from the same moss wd. throw light on this point.) (☞ Quer. if Van Helmont’s6 expt. decisive, because 1. the deposits of the water might equal the loss of the earth & preserve the weight 2. the do. of the air might have the same effect. 3 or the joint do. of both. To verify the expt. a vessel of water sustaining alone a plant shd. be weighed before & after; the vessel being closed by an elastic substance embracing the plant; but this not absolutely decisive because 1. water might pass thro’ the plant into the air. 2. because water might pass from the air thro’ the plant into the vessel. 3. the contents of water & not the water itself might feed the plant. 4. the air or its contents might supply the nourishmt. to the plant. To compleat the expt. therefore water purified from every foreign ingredt. shd. be confined in a vessel; and the vessel kept in a confined body of air: and after the plant be weighed; the water shd. be first weight [sic] & then anylized, and the air also be subjected to the same operations.) Or still more accurately, portions of the water & air sd. be both before & after chemically analized, that the kinds & proportions of their respective parts affected might be known. The agency of heat & light wd. again remain to be ascertained. Also electricity & possible other unknown agents.
From appendix to 15th. Chap. &c on Manures (Composts)
When dung & lime are not immediately great advantage from makg them into composts. If dung be allowed to rot too long, it moulders into earth & become effete. By mixing it with earth it communicates its fetid effluvia, & the whole is preserved. The putrid fermentation cannot be so slowly conducted, but a part of useful matter may be lost. By mixing fresh dung & earth, the loss is diminished greatly.7
When both lime & dung are used, there should be first a stratum of earth, then dung; then earth lime earth, dung &c. always interposing a stratum of earth between the lime & the dung: the reason is that lime, if mixed with dung in the 1st. stage of putrification corrodes & dissipates its effluvia. After the 1st. putrification of the dung, the whole sd. be mixed by cutting the heap perpendicularly with a spade. p. 34, 35.
Severe croppg. after lime impoverishes. This manure most powerf⟨l.⟩ in raising sweet & palatable grasses. A general rule, dung & crop lime & rest. p 36. Lime good for potatoes, if not in contact: bu⟨t⟩ laid on the top of the drills. ibid. Even land ruined by sever⟨e⟩ cropping after lime or marl, will recover, if thrown into pasture & top-dressed with the same manures; for which the best time is towds. the close of the season, so as to leave a rough herbage during winter. 38 Lime properly spread in winter & on snow, as proved by experience. ⟨16.?⟩
Carbonic acid or fixt air compose 40/100 of pure limestone,8 & according to Lavoisier,9 Carbonic acid, contains 28/100 of carbon, or coal, supposed by Hassenfratz10 to be the principal food of plants.
Van Helmonts expt. “But I have learned by this handicraft operation, that all vegetables do immediately proceed out of the water only: for I took an earthen vessel in which I put 200 pounds of earth that had been dried in a furnace, wch. I moistened with rain water; & I implanted therein the trunk or stem of a willow tree, weighing five pounds & at length 5 years being finished the tree did weigh 169 lb. 3 oz. but I moistened the Earthen vessel with rain or distilld water (always when there was need) & it was large & implanted into the earth; & lest the dust shd. be comingled with the earth, I covered the lips or mouth of the vessel with an Iron plate covered with tin, & easily passable with many holes. I computed not the wt. of the leaves that fell off in the autumns—at length I dried again the earth of the vessel, & there was found the same 200 lb. wanting abt. 2 oz. therefore 164 lbs. of wood, bark & roots arose out of water only.”
1. Claude-Louis Berthollet (1748–1822) graduated from the University of Turin with a medical degree, moved to Paris in 1772, and began his celebrated studies in chemistry under the patronage of Louis XVI. Among Berthollet’s many discoveries were the composition of ammonia and the use of chlorine as a bleaching agent (Gillispie et al., Dictionary of Scientific Biography, 2:73–82).
2. The source from which JM took these notes was William Cullen, “The Substance of Nine Lectures on Vegetation and Agriculture,” in Additional Appendix to the Outlines of the Fifteenth Chapter of the Proposed General Report from the Board of Agriculture: On the Subject of Manures (London, 1796).
4. Curl: a disease of potatoes (ibid.).
5. Charles Bonnet (1720–1793) was a Swiss naturalist whose observations and experiments with insects and plants entitle him to be considered a father of modern biology (Gillispie et al., Dictionary of Scientific Biography, 2:286–87).
6. Jean Baptiste van Helmont (1579–1644) was born in Brussels in the Spanish Netherlands and educated at Louvain University where he took a medical degree in 1599. After extensive European travel, van Helmont devoted his career to research in chemistry and medicine. He was actively persecuted by the Roman Catholic Church for his publications. His greatest work, Ortus Medicinae (1648), was published posthumously (Walter Pagel, Joan Baptista Van Helmont: Reformer of Science and Medicine [Cambridge, England, 1982], 2–3, 6–8, 13, 15).
7. The source for this is page 34 of James Headrick’s “Essay on Manures” in Additional Appendix to the … Fifteenth Chapter of the … Report from the Board of Agriculture.
8. At the beginning of this clause, JM wrote in pencil: “See note to p. 4.”
9. Antoine-Laurent Lavoisier (1743–1794), famously known as the discoverer of oxygen and its properties, was one of the founders of modern chemistry. A man of wide interests and indefatigable energy, he was guillotined for his financial interests in the Farmers General (Gillispie et al., Dictionary of Scientific Biography, 8:66–85).
10. Jean-Henri Hassenfratz (1755–1827) was a French chemist who began his career as a master carpenter, then as an inspector of mines. He worked for a time in Lavoisier’s laboratory and taught at the École des Mines and the École Polytechnique, publishing articles in chemistry and mineralogy (ibid., 6:164–65).