A N APPARATUS F O R RAPID ANALYSIS O F MIXTURES O F GASES.
91
100
TABLEOF FACTORS CORRESPONDINGTO
t 144-2
I
Dcgrees Centigmde
10". 11
Factour.
..................
...................0.719
26'. .0.763 2 7 . . ...................0.766 28 ..................... 0.768 29 0.771 30 0.774 .0.777 31.. 32 0.780 3 3 . . . . . . . . . . . . . . . . . . . .,0.784 34 0.787 35. 0.790 36 0.793 37 0.796 0.800 38 39 0.803 4 0 . . . . . . . . . . . . . . . . . . . ..0.806
..................... 0.722 1 2 . . . . . . . . . . . . . . . . . . . . ,0.724 1 3 ..................... 0.727 14 ..................... 15
.....................
16 ..................... 1 7 ..................... 18 ..................... 19 ..................... 20 21. 22 23 24 25 .....................
..................... .....................
0.730 0.732 0.735 0.738 0.740 0.743 0.746
..................
.....................
..................... .................... .....................
..................... . . . . . . . . . . . . . . . . . . ..0.;49
.................... ..................... .....................
XXIIL-AN
..................... ..................... ....................
.o.752 0.754 0.757 0.760
APFARATL-s FOR
RAPIDANALYSIS O F MIXTURES GASES.
THE
OF
Br ARTHURH. ELLIOTT, Pir.13, F.C.S. T h e apparatus is of the type of those in which the various gases are absorbed by the use of liquid reagents added in a certain order. This was carried out by Raoult* in a graduated tube with a stop-cock above and another below, and the upper stop-cock surrounded b y a cylindricil funnel. Bdt the washing out of each reagent before adding a new one, and a somewhat risky manipulation of t h e tube and stop-cocks t o insure measuring the gas without pressure, makes this method troublesome. Wilkinson further modified this method of Raoult, b y introducing another vessel in wliich the burette stood in water, doing away with t h e lower stop-cock. By this means, t h e level of t h e water in t h e burette, and the exterior tube, could be adjusted b y means of a stop-cock on the latter, and the gas measured +F.31. Raoult, Conrpf. rem^'., 187G, 844.
92
A N APPARATUS FOR RAPID ANALYSIS OF MIXTURES OF GASES.
without pressure. This was an improvement over the method of Raoult, but it still left the washing out of the reagents as a drawback. This washing becomes very important in many cases. For example, if we have a mixture of gases rich in olefient gas and ethylene, and after treating with potassic hydrate and pyrogallate of potassium, we wash out the alkali, before adding bromine to absorb the illumiriants (olefient gases). The water necessary to remove this alkali, will reduce the volume of the illurninants as much as two per cent. In the apparatus I have devised, the gas is removed from the absorbant liquid and meamred in another vessel, without washing. T h e apparatus is shown in the accompanying drawing. T h e tube A is of about 125 C.C. capacity, whilst B, although the same length, holds only 100 C.C. from the point D, or zero, to the mark on the capillary tube a t C, and is carefully graduated in T$ C.C. T h e attachments to these tubes below are seen from the drawing, except t h a t the stop-cock I is thres-way and has a delivery through its stern. T h e bottles K and 1, hold about 1 pint each. T h e tubes A and B are connected above with one another, and also with the cylindrical funnel M, b y a series of capillary tubes about 1 millimeter in diameter inside. There is a stop-cock a t G and another a t F, whilst the funnel 11,which holds about 60 c.c., is ground to fit over the end of F above. At E’ ir a piece of rubber tubing u n i t i n g the ends of the capillary tubes, whici: are filed square to make them fit as close as possible. I n beginning the analysis of a mixture of gases, the stem exit of the three-way cock I is closed by turning it so that L and A are connected through the rubber tubing; the stop-cocks F and G are opened, and water is allowed t o fill the apparatus from the bottles K and L, which have been previously supplied. W h e n the water rises in the funnel M,’and all air-bubbles have been driven out of the tubes, the stop-cocks F and G are closed, the funnel 31 removed, and the tube delivering the gas attached in its place. 13y now lowering the bottle L slowly, and simultaneously opening the stop-cook F, the tube A is nearly filled with gas, and the stopcock E’ is closed. The tube delivering the gas is removed, the funnel 31 replaced, the bottle L raised, the bottle K lowered, and by opening the stopcock Cr, the gas is transferred to the graduated tube B. By placing the bottle L on a stand a t about the height of the water in A, the level in B and in the bottle K can be adjusted to t h e
A N APPABATUS FOR RAPID ANALYSIS OF MIXTURES O F GASES.
93
94
A S A P P A R A T l i S F O R R A P I D A X A L T S I S OF J I I S T U R E S O F G A S E S .
zero point, and the s t o p a x k C: is closcd. 'l'lie excess of gas i i i A 1s expelled by opening the stop-cock F and raising tlic bottle 1,. T h e gas remaining in the capillary trtbc betiveeii C' ant1 the vertical part is disregarded, or its ~ a l i i emay be ascertained and a i l al1owanc.c made ; but usually it is too trifling to be worth notiw. Having measured the gas, it i.; i i o w transfcrrcd I)y nicaiis of the bottles I< and L into the tube A, ant1 tlie fliti(1 c.licmicds added by placing th6m in tlic furinel M anti allon iiig tlieiri to flow clown the sides of the tube A slowly, care being takeii / c e ~ ' e to r Ict the fluids run below the level of the top of the vertical tube i l l t h o funnel. I t is best t o have a mark 011 the oiit.;idc of thc funnc.1 a t least threcfourths of an inch above thc top of the lcvcl of the \ eltical tube, and never draw the fluid down below tliis point. llavirig treated the gas with tlie chemical, it is transferred b y means of the bottles, to the tube I3 to be measured. If the chemical gets into the horizontal capillary tube, the passage of a little water from the bottle K will remove it, before transferring t h e gas. W h e n tlie gas residue is i i i B, and the fluid of i\ has been acljusted a t t h e inark C on the horiLontal tube, the stop-cock G is closed, the bottle I< is lowered till the level of liq.uid in it arid i n the tube U are is now filled the same, and the reading is then inade. T h e tube with the chemical, just used a. absorl)ant, and watci,, by turning the stem of the three-way cock I, so that it coinmiinicatcs with A, and also opening the stop-cock F, the contents of the tube can be run out, and water run through the funnel 31 to clean the tube for a n e w absorption. W h e n the tube is clean, by turning the stopcock I so that A and 1, are connected, the water is poured inLo A, and the whole is ready to receive the gas i n U for new treatment By this method a mixture containing carbonic iicid, oxygen, illuminants and carbonic oxide, can be analyzcd in froin 2 0 to 30 miiiutes, according to t h e amount of IJracticc tlit. operator has had with tlie apparatus. Compared with Orsat'* apparatiis, the work can be dolie with the above described apparatus in one-fourth the aniouiit of time, and with identical results. T h e water used in the apparatus should have the same temperature as the room in whieli t h e analysis is made; and b y careful handling, little or nonc of the chemicals get into tlie bottle I,. IYhen working in a warm place, the tube U should be surrounded with a water jacket to prevent change of volume in the gas while under treatment. A\
School of Mines, Columbia College, N. T
