The Repertory of arts and manufactures [afterw.] arts, manufactures and agriculture

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Էջ 171 - I found it was, at feven feet, (for a large fwelling rendered it unfair to meafure it at five or fix feet,) a trifle above thirty-four feet in circumference ; and, in 1778, I found it had not increafed above half an inch in nineteen years. This more entire remain of longevity merits fome regard from the lovers of trees, as well as the hollow oak at Cowthorp, in Yorkfhire, which Dr. Hunter gives an account of in his edition of Evelyn's Silva, and calls it, forty-eight feet round, at three feet.
Էջ 177 - We may lay it down as an incontestable axiom that, in all the operations of art and nature, nothing is created ; an equal quantity of matter exists both before and after the experiment : the quality and quantity of the elements remain precisely the same, and nothing takes place beyond changes and modifications in the combinations of these elements. Upon this principle, the whole art of performing chemical experiments depends...
Էջ 112 - The great degree of fenfibility of this teft would leave very little reafon to fearch for any other, were there reafon to believe that it is always a teft of the exact point of faturation of acids and alkalies, which the following fact feems to call in queftion. I have obferved, that a mixture of phlogifticated nitrous acid with an alkali, will appear to be acid, by the teft of litmus, when other tefts, fuch as the infufion of the petals of the fcarlet rofe, of the blue iris, of violets, and of other...
Էջ 401 - I will take one acre of clover, which at one cutting will produce from fourteen to eighteen tons of green vegetable matter, and about three tons of lime; this, when...
Էջ 187 - Procure three earthen or wooden veflels of different fizes and apertures, one capable of holding two quarts, the other three or four, and the third five or fix : boil a quarter of a peck of malt for about eight or ten minutes in three pints of water; and, when a quart is poured...
Էջ 121 - ... the oil of its colour ; while the oxide, attracting the mucilage, may contribute to the fame end. How far this theory may apply to the explanation of the foregoing experiments, I do not pretend to determine, It is remarkable, however, that one of the earthy fubftances, viz.
Էջ 292 - Fig. 3, reprefents the diaphragms and tubes enclofed within the drum, the diaphragms being compleated by having their plates fcrewed on; in thefe plates are fixed two valves G, G. Oppofite to which are two others, one in each diaphragm, fo correfponding that at the opening of one the other is clofed, and vice verfa. Thefe valves are balanced, and held on trunnions, fo that, in every fituation of the diaphragms, they may uniformly obey the impulfe by which they are opened and fhut; the manner in which...
Էջ 170 - ... inches in two hundred years. But this oak cannot properly be called old. The annual increafe of very...
Էջ 113 - ... in a mixture of vitriolic acid and water, of about the degree of acidity of vinegar ; and it may be neutralized, as it is wanted, either by means of chalk, or of the fixed or volatile alkali. But it is...
Էջ 112 - ... the fame liquor to be alkaline, by turning green fo very evidently as to leave no doubt. At the time I made this difcovery, the fcarlet rofes and feveral other flowers, whofe petals change their colour by acids and alkalies, were in flower.

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