. Journal . pcocks aretherefore placed on the ungraduated side, , the side fromwhich the apparatus is manipulated. This reversal of themore usual arrangement leads to greater compactness byavoiding the use of a separate stand for the reading tele-scope, and permits the ready employment of the fineadjustment for levelling the mercury as described below. The gas having been introduced into the measuringvessel, the stopcock at the top of the level-tube is openedand the mercury roughly levelled. The stopcock leadingto the mercury reservoir is then closed in order to preventoscillation, and the
. Journal . pcocks aretherefore placed on the ungraduated side, , the side fromwhich the apparatus is manipulated. This reversal of themore usual arrangement leads to greater compactness byavoiding the use of a separate stand for the reading tele-scope, and permits the ready employment of the fineadjustment for levelling the mercury as described below. The gas having been introduced into the measuringvessel, the stopcock at the top of the level-tube is openedand the mercury roughly levelled. The stopcock leadingto the mercury reservoir is then closed in order to preventoscillation, and the levelling completed without taking oneseye from the reading telescope by gently turning the milledhead of the screw clip so as to increase or diminish thecapacity of the india-rubber tube referred to above. • The plus of tins stopcock should taper but little, in oncer thatit may nut be forced out by the pressure of the mercury. >•: JOUKNAL OF THE SOCIETY OF CHEMICAL INDUSTRY. [Feb. £?, 190S. 1 IG. 1. In order that Ibe surfaces of tie mercury may be well illuminated a quarter-plate focussing screen has its upper .•nil -vitli i ;.i .1 a 2 electric lamp (not i i the centre an - behind it. A split tube attached lo this Is slid up i down the rod, P, until the lower i ui i- iu-t above trie level of the me eury, thelamp being brought into usi daylight b -i • ni> strange so many chemists still followBnnsen in employing measuring tubes graduated in niilli- metres, although the original excellent reason fur thissince ceased to exist in ordinary troublesomi necessit> of coustuntl) referring to »calibration table seems to hr accompanied bj no compen-sating and at the present nine tin rs ol graduation in a good measuring tube are so small tinoften be igni red, and always I • Tube 11, Iig. i cylindrical bulb i i capacity markedly exceeding M ■ ■ the upper end to a small stopcock, andat tin-lower to a U-tnbe, of which the d li
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
