210 FE, M. Walton—Inquefaction and Cold produced 
every instance liquefaction ensued. Apparently the hydrated 
rie was hit for the sake of its water, and the first reac- 
on to be appropriation of water by KOH, which is 
ee followed by metathesis in most cases. 
Liquefaction in the examples given above, however, can- 
not be explained in this way. Neither is ie metathesis, 
and evidently double salts are not formed. 
Having mixed equivalent weights of ZnSO,.7H,O and 
‘Na,SO,. 10H,0, the composition ‘of. the resulting solid part 
was found not to be that of a double sulphate, there being an 
excess of Na,SO,. 
Equ uivalent weights of CaCl,.6H,O and Ca(NO,),.4H,O 
so mixed, also of Fe,Cl,. 12H, O and Fe (NO,),. 18H,0, eo 
view to analysis, but in each case the thin liquid disappeared 
cavirely into the plaster plate used for absorption, leaving only 
a stain visible. 
heory.—These examples must be similar in nature to mix- 
tures of salts with i ice, which result in liquefaction, and solution 
of the salts. 
the “i snes of Seier nee. 
w that the molecules of a body are in a state of con- 
stant excilation, and that if a salt solution be placed in contact 
with pure water, diffusion takes place rege ae molecules of 
sat are sctally distributed throughout the 
So, too, when the solid is placed in vain Bladen follows, 
or, in other words, diffusion. Now, when a salt and water, 
both in the solid form are in contact, there is probably the 
same tendency to interpenetration. But a mixture of water 
and salt molecules cannot remain in the solid form except at a 
low temperature, and the rigidity of the solid state is overcome, 
because oscillations of the pioie and the salt molecules coope- 
rate to produce a greater motio 
Graham found that althou h sodium chloride is not at all 
deliquescent, yet the biAiurated: solution has a great affinity for 
ater. Therefore when the smallest quantity of the salt 1s 
once in solution the first step is taken and the melting of the 
ice continues rapidly. If this is the true explanation of the 
action of sodium chloride on ice the problem is solved. 
Pies salts capable of metathesis are used this physical phe- 
menon is complicated by chemical reaction. Liquefaction 
Stobably results when CaCl,.6H,O and Ca(NO,),.4H,O are 
* Proceedings Amer. Assoc. Adv. Science, vol. xxix, p. 293. 
