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71)

calcium chloride. This prevents loss of moisture from the*
weighed apparatus.

Soda lime* is sometimes used for the* absorption of carbon
dioxide*. This is made by fusing together sodium hydroxide and
lime, the product being granulated during the cooling process,
The chief objection to this use of soda lime is the, fact that it is
HOinewhat uncertain in its act-ion and the absorption of gas in
liable to be incomplete unless the moisture; content is kept
within fairly narrow limits (about 15 per cent).

Determination of the Carbonate JRadical: (frnvhm'trir Method. Procure.
the following parts for jiHHrmblinp;;

1 dropping funnel, 50 ee, with one-hole rubber stopper,

1 short, wide iiask, 75r<% sueh an is used for fat. extractions, with two-hole

rubber stopper,

• 1 condenser with body nut more than (\ inches long,
3 I'-tubes with corks to fit,
1 I "-tube with ghiss stoppers,

1 Htraight drying tuh»* with one-hole nthber wtopper,
1 net (leiHsliT **p«»t!i>tli bulbn" or h«I!»« tif WHIK* other approved form,
1 aspirator bottle, tubulati'd near hottotn, with one-hole rubber stopper*

to fit,

1 piece gliiHH tubing, about 2 fn»t l»y 12 inrh, for mtpporting iippamtim,

2 (•htitipK,

2 pinrli rocks,

1 wniill wrew ehimp rliofTuiait ,Mt?r<*wi,

2 n*torf stunds, *
titan and rubber tubing fur cnimcrtionH,

Fill and rtmnert the apparatus in tlie manner previously <IeHeril»ed.
Thi- drying ttibe.H »n* lilli*«i nearly to the Hide arms with a Rood gnide of
gnuitiiar rnlriniti rhifiride. A low plug of c(»tton is plrnvd on tup of the
chloride ami thon n rork in pri*H«rcl in until the top in stlnnit 2 mm b*«low the
top of tlti* tube. Into the rup thus formed meltrd pumffin in poured a« it
winling njiiferiiil. If hubblea appi'nr in tbe pamfHn after cooling; they >ir«*
removed by remelting the xtirfare by a flame.

When filling the absorption btilbii witlt potuHKiuiii hydroxid*! nohttioti
th<! latter shottid not be warmer tliitn the nir of the rt»om. The bulbn
are n<iw di'tiirlifrl from the nppitrntitM find the solutiim in rlrnwrt in through
A tube ftttiu'hefi ft!, n, xuctiott being applied at /». The nohttion Hhouttt
ahoitt luiif fill lli<f* bulb r wh«*n air is bubbling through. 'I4he grotmd''
gliiKH joint b<*tween the drying tube h anc! I hi* bulbn should be lightly eoateil
with vuwliiii* i»id tin* tul»e then twisted on until it fitn rlowly «*nough tlmt
there will lii! net danger <»f IrHiHcm'ug during the course of an experiment.
Any hurpluK viweliiit* is remc*ved frt»m the «>iif«.ide *»f the joint.

I

PW
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