Journal . ;inal solution. Knoidt Iiius shown that theelTect of supcrroolinn may In- expressed hy the eipuition : A = ^rr , where ( - the observed Covalue. C = the true depression, .<? = degrees ofHupeivoolinp. and /C = a constant. The latter isfound hy determinint; the freezinj; point fordifferent ilegrees of supeirooling ; if llie valuesfound are plotted as ordinates and the degrees ofsupercooling as ahsi-issic, an approximately straightline is obtaineil from which tlie true freezing pointfor .supercooling nil may l)e found. K is thencalcvdated from the above formula. For sucrosesolutions
Journal . ;inal solution. Knoidt Iiius shown that theelTect of supcrroolinn may In- expressed hy the eipuition : A = ^rr , where ( - the observed Covalue. C = the true depression, .<? = degrees ofHupeivoolinp. and /C = a constant. The latter isfound hy determinint; the freezinj; point fordifferent ilegrees of supeirooling ; if llie valuesfound are plotted as ordinates and the degrees ofsupercooling as ahsi-issic, an approximately straightline is obtaineil from which tlie true freezing pointfor .supercooling nil may l)e found. K is thencalcvdated from the above formula. For sucrosesolutions K =0 015 and for milk A=0017. The apparatus used in the determinations isshown in the illustration. A Dewar vacuum vessel,I. of 10 cm. itifernal iliamcli-r and Hi cm. internal. depth, was closed with a cork dLsc, 2, al>out 1 inchthick, glued to a metal plate and ring, 3, and thecover thus formed could be made air-tight by arubber ring, 4. Through the middle of the corkdisc passed a ^lass tube, 5, of 3-8 cm. internaldiameter, the joint with the metal plate beingmade air-tight with glue-cement. The cork discalso carried a copper inlet tube for ether and air,an outlet tube, a thermometer graduated to OOP a siphon, !), connected with the lower end ofthe tube, 5, and so designed that ether could bea<lmitted or withdrawn from the IJewar freezing tube, 10, was a thin glass test-tube,;j o cm. internal diameter ; it was closed by a cork,1 inch thick, carrying the thermometer, 11, aspiral glass stirrer, and a small opening, 13, pro-vided with a stopper. It also carried anotherthermometer, not shown in the figure, graduatedto 01 C, to indiiat* the degree of freezing point was determined in the followingmanner :—Kther, ilried ov
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
