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there are two things more required: such a mixture as will af. ford to the vegetables not onl proper nourishment; but also such a one as keeps humidity as long as the usual drought makes it requisite ; for nothing grows, even in the most exquisite soil, without water. The best compound, therefore, ought to be adapted to the nature of the soil, the exposure, the climate, and the common temperature of the weather; as I have proved more at large in another place.—In the mean time it will be easily found, that chemistry is of the same iroportance to agriculture and all the more particular branches of rural cecoñomy, that astronomy is to navigation. - The arts and mechanical trades, are occupied with the melioration of raw materials. One part of them, from beginning to end, is a series of chemical operations; others are more mechanical ; however there is hardly one of them which contains not one cr more problems whose more perfe&t solution depends upon chemistry only. What a number of years must have elapsed before they arrived by chance only, or by unpremeditated experiments, to their present perfection; or before they learned to avoid all ocA perfect knowledge of the raw mate. rials, often furnishes the best instrućtions, in a direét way. And, it has been hitherto a great misfortune, that the practical part of the arts has been kept very secret: but since the French Academy of Sciences has begun to remove this obstacle, we have the most certain expectations of their G 2 - quick

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