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MANURES. 49 



Burr-millstone makers and stucco-plasterers were the only persons ac- 

 quainted with any of its uses. From a manufacturer of the former I procured 

 a bushel, which enabled me to begin my agricultural experiments, and I faith- 

 fully improved and extended them as I obtained more means. 



A quantity, imported as ballast, twenty tons I believe, in a vessel engaged 

 in the London trade, and thrown out on a wharf, without knowledge of its 

 value, was the first important foundation on which this extensive improve- 

 ment to our husbandry was established. 



With this, Mr. BARGE began the business of pulverizing the gypsum; first 

 in a hand, subsequently to this in a horse-mill, and soon afterwards it was 

 carried on in a water-mill. When I had convinced myself of its efficacy, I 

 disseminated the knowledge I had acquired through many parts. But my 

 success in obtaining credit to my assertions, or in procuring assistance in 

 prosecuting my experiments, was, for a length of time, very limited and dis- 

 couraging. I had no concern in the manufacture, or any other object in the 

 communications, but one founded in a desire to propagate a knowledge of this 

 valuable acquisition.'' 



The soils to which it is the most congenial are the light, 

 dry, sandy, gravelly and chalky; to heavy loams, strong clays, 

 and to wet land, it seems to yield no benefit, unless the former 

 happens to be well limed. 



Upon exhausted land, or upon soils containing little vegeta- 

 tive mould, or deprived of putrescent manure, it will prove 

 powerless, but it succeeds well after an application of dung, 

 or of green crops ploughed down. It produces, also, more 

 effect in dry than when laid on in wet weather. 



A watery temperature, at least, arrests its effects, and seems 

 even to suppress them altogether if the gypsum has been cal- 

 cined; but it should be observed, that this only occurs if rain 

 falls soon after its application, for if it happens previously, its 

 moisture upon the plants will be found very useful. This pe- 

 culiar property has given rise to many mistakes, and occasion- 

 ed much of the prejudices which exists against it in certain 

 localities. 



The late Col. JOHN TAYLOR, of Caroline County, Virginia, 

 states in substance that he sows of plaster from three pecks to 

 one bushel per acre. Sown on clover, especially red top, in 

 the spring, its benefit is very striking. The best way of using 

 it is in the spring upon the long manure of the preceding 

 winter, to be ploughed in with it. He regards it as an import- 

 ant ally, but by no means as a substitute for manure. There 

 should be intervals allowed of two, three, and four years, 

 between applying it to the same land. 



"Within the last ten years," says Col. TAYLOR, "I have 

 used between two and three hundred tons of gypsum, in a 

 variety of experiments, which have produced the conclusion 

 that it increases very considerably the product of vegetable 

 matter in almost all its forms. Except when sown on clover, 

 which it benefits almost at all seasons, I have found it succeed 

 best when covered. Its immediate benefit to Indian corn is 

 5 



