The American journal of science and arts . extent of the vacuity which appears,when the glass recipient is held uppermost, and which disappears when itis held lowermost, the weight of the mercury acting upon the elasticityof the tubes, always causes a minute change; but by the smallest bub-ble of air, the effect is very much augmented. The Eudiometer shouldbe introduced into the vessel whence the gas is to be taken, about tenper cent, more than is necessary being drawn in by opening the orificeand duly drawing out the rod. The Eudiometer being lifted from themercury, with as little change of p
The American journal of science and arts . extent of the vacuity which appears,when the glass recipient is held uppermost, and which disappears when itis held lowermost, the weight of the mercury acting upon the elasticityof the tubes, always causes a minute change; but by the smallest bub-ble of air, the effect is very much augmented. The Eudiometer shouldbe introduced into the vessel whence the gas is to be taken, about tenper cent, more than is necessary being drawn in by opening the orificeand duly drawing out the rod. The Eudiometer being lifted from themercury, with as little change of position as possible, the rod may beadjusted accurately to the point desired. A momentary opening of theorifice causes the excess to escape. The gas thus measured and in-cluded, is then easily transferred to the principal Eudiometer, by in-troducing the apex of the subsidiary instrument under the funnel^ (se,eP, fig. 4.) opening the orifice, and forcing the sliding-rbd home. Vol, X.—No. 1, W 7^ 3^r. Hetre^s hnproUcfl iikidiomeie-i Kg. ^.. The method of analyzing atnnospherie air by means of theseinstruments, is as follows. Supply the subsidiary Eudiome-ter with its romplemept of hydrogen gas, by introducing theapex of the glass recipient into a bell glass containing, overmercury, the gas in question, and drawing out the slidingrod, the orifice being kept open only while above the surfaceof the mercury, and inside of the bell. The gauge cock (C, fig. 4.) of the principal Eudiometerbeing closed, and that which opens a communication betweeothe recipient and the funnel F open, and the instrumenthaving been previously thoroughly filled with mercury, an4placed over the mercurial cistern, as already mentioned, io-troduce into it, through the funnel, the gas which had beeaincluded in the subsidiary instrument (fig. 5) ; next shut offthe communication with the mercurial cistern, re-establishthose between the recipient and the rod and gauge, and pushthe rod into its tube up to the hilt.
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