Nowadays, in order to obtain that same crop of 500 bushels of potatoes, we must plough every year a surface of four acres, plant it, cultivate it, weed, it, and so on; whereas with the glass, even if we shall have to give perhaps, to start with, half a day's work per square yard in order to build the greenhouse--we shall save afterwards at least one-half, and probably three-quarters of the yearly labour required formerly. These are _facts_, results which every one can verify himself. And these facts are already a hint as to what man could obtain from the earth if he treated it with intelligence. V In all the above we have reasoned upon what already withstood the test of experience. Intensive culture of the fields, irrigated meadows, the hot-house, and finally the kitchen garden under glass are realities. Moreover, the tendency is to extend and to generalize these methods of culture, because they allow of obtaining more produce with less work and with more certainty. In fact, after having studied the most simple glass shelters of Guernsey, we affirm that, taking all in all, far less work is expended for obtaining potatoes under glass in April, than in growing them in the open air, which requires digging a space four times as large, watering it, weeding it, etc. Work is likewise economized in employing a perfected tool or machine, even when an initial expense had to be incurred to buy the tool. Complete figures concerning the culture of common vegetables under glass are still wanting. This culture is of recent origin, and is only carried out on small areas. But we have already figures concerning the fifty years old culture of early season grapes, and these figures are conclusive. In the north of England, on the Scotch frontier, where coal only costs 3s. a ton at the pit's mouth, they have long since taken to growing hot-house grapes. Thirty years ago these grapes, ripe in January, were sold by the grower at 20s. per pound and resold at 40s. per pound for Napoleon III.'s table. To-day the same grower sells them at only 2s. 6d. per pound. He tells us so himself in a horticultural journal. The fall in the prices is caused by the tons and tons of grapes arriving in January to London and Paris. Thanks to the cheapness of coal and an intelligent culture, grapes from the north travel now southwards, in a contrary direction to ordinary fruit. They cost so little that in May, English and Jersey grapes are sold at 1s. 8d. per pound by the gardeners, and yet this price, like that of 40s. thirty years ago, is only kept up by slack production.