The harvesting of hay is one of the most important operations which the farmer is called upon to undertake, and requires for its successful accomplishment, great activity and industry, close attention and skillful management. Of the time when it should be cut, we have already spoken. Of the hight at which it should be cut, it may suffice to say that this should vary according to circumstances. Where the meadow is chiefly of well grown herdsgrass, (Timothy,) and the season hot and dry, it is not deemed safe to cut closer than below the second joint, (see pages 84-85,) but where other grasses chiefly prevail, and especially if the meadows be partially exhausted and the crop light and fine, and the season a moist one, it may well be cut much closer, leaving perhaps as little as may be. Wet meadows or swales, yielding what is called "fresh hay," and upland meadows, receiving a top-dressing soon after, may be cut very closely. Grass, in its best estate, being universally acknowledged to be unsurpassed for food, and being incapable of preservation on account of the amount of water it contains, the problem in hay-making at first blush would seem to be, how to deprive it of water in the easiest and quickest manner, to an extent sufficient to enable it to be stored with safety; and the answer which most naturally suggests itself to this is, to expose it as fully as possible to drying winds and sunshine; but in practice this method is found to result in a hardening and brittleness of the stalks and leaves, and a loss of sweetness, flavor and aroma. The deprivation of water is not the only point to be considered. In grasses at the proper stage for cutting, we find the nutritive juices to hold much sugar, gum, vegetable albumen, &c., which are capable of undergoing certain spontaneous changes, in regard to the nature of which we are very imperfectly informed. One of these, the process of fermentation, is one of the most obscure of all chemical processes, but happily although science may not yet be able to explain fully all which occurs, practice has not left us ignorant of its results. It is a well established fact that a partial sweating of grass is needful in the process of curing, in order to develop and secure the best properties of good hay. It is also important that this should not be violent, but gentle and gradual in its progress, and that it be arrested at the proper stage, as otherwise the changes attending it would result in damage and loss. In such sweating, which is a partial fermentation, there take place many different chemical changes, which together with their effects are more fully set forth than I have ever scen elsewhere, in a communication received from Dr. Samuel L. Dana, well known as a distinguished chemist, in reply to a note of inquiry touching this matter, and which is as follows: "Growing grass is a mass of ferments and fermentable principles, combined with neutral substances and mineral matters. By ferments, I mean matter capable of exciting fermentation. By fermentation, I mean a change in the state of a body attended with production of carbonic acid and alcohol. By fermentable principles, I mean bodies capable of undergoing fermentation; or simply a change without loss of substance. By neutral principles, I mean fatty and waxy matter. By mineral substances, I mean the earths and salts, which form the ash of burned grass. The elements above enumerated form the skeleton of the grass, which is clothed with green drapery, composed of a neutral substance, which like the coloring matter of blood contains iron as one of its components. The whole plant is rendered plump and soft by an excess of water-the sap of the vegetable. The ferments are composed of four chemical elements-carbon, oxygen, hydrogen, and nitrogen. They form a distinct group, composed of albumen, gluten, &c., united to sulphur and phosphorus. The fermentable matters also form a distinct group of well defined vegetable principles, all connected by a common bond, and behaving much alike under similar circumstances. This group comprises: 1. Woody fibre. 2. Starchy matter. 3. Gummy matter. 4. Sugary matter. These are composed of carbon, hydrogen and oxygen, only the last two being in just the proportion to form water. 5. Jelly matter composed like the above, but with oxygen in excess. If the members of these two groups were in a perfectly dry state, no change would occur. They are capable of acting on each other only in the presence of air and moisture. This is the condition of freshly cut grass, free from dew or external wet. The question then presents itself, what are the changes occurring in hay-making. 1. The ferments begin, almost as soon as life ceases, to act on the sugary matter. This is changed by a true fermentation into carbonic acid and alcohol, accompanied by various ethers and essences-dependant on the peculiarity of the ferment. This last always undergoes change during its action on fermentable matter. Both lose weight from the escape of gas. 2. The starchy matter cannot ferment like sugar. Certain albuminous ferments rapidly convert starch without loss of substance into gum, and ultimately this into sugar. This is effected by diastase, a substance produced by fermentation. Hence malt quickly changes the starch into gum and sugar in the brewer's mash. Starch is also changed into gum and sugar, by the long action of weak acids, even by very weak vinegar, but we have no evidence that carbonic acid evolved during fermentation so acts, nor that vegetable acids, existent in plants, change starch to gum and sugar, as they promote the conversion of sugar into alcohol. In wet hay, it is possible that the starch swollen by previous heating may be converted to gum by exposure, an effect well known to be produced on starched clothes in damp weather. They iron limpsy. 3. Gummy and jelly matters-these change not. Gum is already food in a soluble state, but by prolonged wet, the gum becomes acid. 4. The woody fibre will undergo no change in hay-making, unless by prolonged wet. In this case, ferments act on it, and it undergoes change with loss of substance. 5. The neutral bodies-fat, wax, and the green drapery suffer change by converting grass to hay, even in the most favorable weather. I do not know the nature of this change. It is quite obscure. It is connected no doubt with the formation of alcohol and ethers, during the fermentation of the sugar, and is attended by a loss of fat and wax. 6. The mineral matters change not in hay-making so as to cause any loss of substance. These various changes occur in curing in the best manner grass into hay. There is in this case, a certain loss of substance. Each species of grass loses in proportion to its amount of ferment and fermentable matter, modified by the amount of sap, and by the weather. It is certain, cure hay how you may, that a loss of vegetable substance occurs. Experiments are yet wanting to determine if grass rapidly dried by artificial heat, preserves its nutritive powers unimpaired. If so, then artificial drying would require the dried grass to be pressed like screwed hay, to exclude air and moisture; for the best dried grass is greedy of the last. If it becomes moist, loss will occur. This loss is due chiefly to the change of sugar into carbonic acid, alcohol and volatile essences-the ethers derived from alcohol. This occasions a loss of actual nutriment. All we get in return is apparently the smell of new made, or making, hay. But this is more than the smell of a dinner, which you know was decided long ago to equal the jingling of money. This odor, the aroma of new hay-making in the cock, is probably worth more than the weight of the lost substance. I believe it is the result of experience, that all cattle eat hay, which has given off its odor by sweating in the cock or mow, better than that which has not undergone that process. Hence if artificial drying were practicable, it would not be advisable. So a bright, hot sun, shining in an atmosphere whose degree of moisture is far below saturation, rapidly dries grass, without making it into hay. If this sun-dried grass is cocked up, it rarely sweats and fills the air with its grateful fragrance. In all its relations, sugar is the most active cause of the loss of weight and nutrition in hay-making. The amount of loss depends on the amount of sugar and the activity of the fermentation. After the alcoholic production has ceased, if the hay is damp, then the alcohol is converted into various acids, as the ferment becomes acid or alkaline. Very little loss is due to any change on starchy matter. It is merely converted from an insoluble to a soluble state, from starch to gum, probably without loss of nutritive power. Still less loss is due to gum-changes. Gum may become sugar by the action of ferments; but this change is not probable in haymaking. The loss then would be consequent on the production of alcohol. The loss of fat and wax, in connection with formation of alcohol, has been alluded to. These escape volatile in part, and next to sugar, are the most prolific sources of loss. But the fat and wax |