376 



Essays on Jlgricultv.re. — No. V 



Vol. III. 



average produce is between 50,000,000 and 

 60,000,000 gallons, five-eighths of which are 

 red, and three-eighths white wine, the whole, 

 or nearly so, being suited to foreign demand. 

 In very favorable years the production will 

 amount to 75,000,000 gallons." 



Ef^i^ays on Agriculture.— No. V. 



BY JOSEPH CLOUD. 



Having noticed the effects produced by the 

 process used in the preparation of calcium for 

 its application and usefulness in agriculture, 

 it becomes necessary, in order to understand 

 its mode of operation, to have a distinct view 

 of the important properties of calcium in the 

 different states in which it presents itself. — 

 1st. x^s a carbonate. 2d. Hydrate. 3d. Su- 

 per carbonate. Carbonate of calcium is 

 nearly insoluble in water. The hydrate is 

 very soluble ; it soon, however, combines with 

 carbonic acid, thereby loosing its solubility ; 

 but as it arrives at the state of super-carbo- 

 nate the solubility is permanently restored. — 

 As carbonic acid is of such vast importance 

 in agriculture, and so intimately connected 

 with what may be said on the operations of 

 calcium and the food of plants, it may be 

 proper to notice its constituents before enter- 

 ing into their consideration. 



Carbonic acid, at the common temperature 

 and pressure of the atmosphere, is a colorless, 

 inodorous, and elastic fluid. It is a compound 

 formed by a chemical union of oxygen gas, 

 one of the constituents of the atmosphere ; 

 and carbon, the woody parts of vegetables, ei- 

 ther by combustion or putrefaction. Calcium 

 is usually employed in agriculture in the state 

 of hydrates — spread on the surface of the 

 ground, where it is either suffered to remain 

 as top dressing, or mixed with the earth by 

 the plough or harrow. Whichever way it 

 may be used the same important effect, that 

 of combining with carbonic acid, will neces- 

 sarily be the result. Mixing it with the other 

 earths may however serve to aid in the im- 

 provement of the texture of the soil by ren- 

 dering it more or less retentive of moisture. 

 Its chief importance abstractly from being one 

 of the necessary constituent of the food of 

 vegetables, is that of its strong attraction for 

 carbonic acid ; consequently combining with 

 euch as may be produced by the decomposition 

 (which it serves topromote)of the putrescent 

 matter in the earth. It also attracts a consid- 

 erable quantity from the atmosphere. By this 

 double operation it treasures up a quantity of 

 carbonic acid until it becomes a super carbo- 

 nate, in which state of solubility it is pre- 

 pared to furnish the two great essentials of 

 vegetable food — carbon anil calcium. It may 

 here be proper to notice the effects produced 

 by the excessive use of calcium. Every prac- 



tical farmer is doubtlessly acquainted with 

 the sterility produced by throwing quantities 

 of oxyde of calcium in heaps, and suffering it 

 to remain until its combination with water 

 reduces it to the state of hydrate and conse- 

 quently soluble. A portion of the solution 

 becomes absorbed by the earth, and although 

 the undesolved hydrate may be removed, the 

 spots on which it was deposited will remain 

 destitute of vegetation for a longer or shorter 

 period in proportion to the quantity of hydrate 

 of calcium absorbed, and the quantity of car- 

 bonic acid required to change it to a state of 

 super carbonate. During the period of un- 

 productiveness produced by the strong affinity 

 existing between the hydrate of calcium and 

 carbonic acid, no food can be prepared to sup- 

 port vegetation. Hence it appears that an 

 excessive use of calcium will prove pernicious 

 for some time, for the reason suggested, that 

 of requiring more carbonic acid than the pu- 

 trescent matter in the soil, to which it is ap- 

 plied, is equal to furnish. The diversity of 

 opinion that prevails respecting the quantity 

 of calcium that can be advantageously used, 

 renders it desirable that something like a 

 reasonable standard .should be introduced to 

 prevent a useless waste of capital in its ex- 

 cessive use, which there is reason to believe is 

 sometimes the case. Unfortunately, however, 

 we are not in possession of sufficiently conclu- 

 sive practical facts from which to form an opin- 

 ion. The observations and experiments on this 

 important subject seem rather to have been di- 

 rected to ascertain the quantity of calcium that 

 certain soils would bear without materially 

 injuring vegetation, than to determine the 

 quantity necessary to render soils most pro- 

 ductive at the least expense. The results 

 have however established the important prac- 

 tical fact, that the quantity will be governed 

 by the amount of putrescent matter existing 

 in the soil on which it may have been used. 

 These results naturally lead to the conclusion 

 that soils containing the most putrescent mat- 

 ter will bear the most calcium without injury. 



Oraiii measure. 



Persons who cannot conveniently procure a 

 half bushel — a peck measure, &c. of the or- 

 dinary construction, may make light square 

 boxes, that will answer for the present pur- 

 pose very well. 



l.st. A box that wi'l measure inside 10^ 

 inches square, and the .same in depth, will hold 

 half a bushel, and only a table spoonful 

 over. 



2d. A box that will measure within 8 inches 

 .square and 8 4-10 inches in depth, will hold a 

 peck. 



3d. A box measuring within 6i inches 

 square, and 6 3-8 inches in depth, will hold four 

 quarts grain measure. 



