. Preventive medicine and hygiene. he gas buret. In this case it is advisable to discard thefirst filling of the gas buret A in order to get rid of the air in the rubbertubing and connections. About 4 minutes are required for an accuracy is about 1 part in 10,000. The air buret A, which is enclosed in a water jacket 0, consists ofa wide, ungraduated and a very narrow graduated portion. This isdivided into 100 divisions, each of which corresponds to 1 part in 10, lowest division is marked 0 and the numbering is upward from thispoint. Any difference between a reading at or ne
. Preventive medicine and hygiene. he gas buret. In this case it is advisable to discard thefirst filling of the gas buret A in order to get rid of the air in the rubbertubing and connections. About 4 minutes are required for an accuracy is about 1 part in 10,000. The air buret A, which is enclosed in a water jacket 0, consists ofa wide, ungraduated and a very narrow graduated portion. This isdivided into 100 divisions, each of which corresponds to 1 part in 10, lowest division is marked 0 and the numbering is upward from thispoint. Any difference between a reading at or near zero and a second 674 COMPOSITION OF THE AIR reading is thus shown by the scale in volumes per , there hcinf:no calculations or corrections. The absorption pipette D is filled to the mark E with a 20 per of caustic potash through reservoir I. The control tube 0 en-closed in the water jacket is used to correct for variations in the tempera-ture of the sample during the analysis. It is connected with the potash. FlQ. 81.—Portable Haldane Apparatus for Small Percentages of Carbon DiOXID. pipette D by the tube H, which has a mark K. The pressures underwhich the readings are made are maintained constant by adjusting thelevels of the potash solution to the marks E and K. To compensate forvariations of temperature of the water jacket 0, air is blown throughthe tube N, thus agitating the contained water. The technic of an analysis is summarized as follows: (1) Open the 3-way cock B to the air to be examined and raisethe mercury bulb C to expel the air in the buret A. Lower the mer-cury bulb and hang on the adjustable rack F so that the sample isdrawn in and the level of the mercury falls to near the zero mark. (2) Open the cock M to the air for a moment and then turn it CAEBON DIOXID 675 so as to connect the control tube with the potash solution in the tube H. (3) Turn the cock B so as to connect the sample with the potashpipette D. (4) Squeeze the rubber tube o
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Keywords: ., bookauthorwh, bookcentury1900, bookdecade1910, booksubjecthygiene
