644 
Proceedings of the Royal Society of Edinburgh. [Sess. 
Table No. 4. 
Designation of Salt 
KC1. 
KBr. 
KI. 
RbCl. 
RbBr. 
Rbl. 
CsCl. 
CsBr. 
Csl. 
Excess of sum of dis- ^ 
placements of salt and { 
water above that of j 
saturated solution ' 
7-010 
5-422 
5-074 
6-641 
7-422 
3-411 
-6-711 
-0-317 
- 10-237 
Designation of Salt 
KClOg. 
KBr0 3 . 
KlOg. 
BbClOg. 
BbBrOg. 
RblOg. 
CsClOg. 
CsBrOg. 
CsIOg. 
Excess of sum of dis- h 
placements of salt and ! 
water above that of f 
saturated solution 1 
2T4 
-5-65 
19-26 
-0-23 
3*69 
10-03 
-0-12 
8-78 
0-79 
In the Ennead MR the difference of the behaviour of the caesium 
salts from those of potassium and rubidium is very marked. In the 
case of caesium iodide the displacement of the saturated solution is 
fully 1 per cent, greater than the sum of those of the salt and water which 
it contains. 
In the case of the salts of the Ennead MR0 3 , given in the third and 
fourth lines of the table, it is only in the case of bromate of potassium that 
the displacement of the saturated solution shows a marked excess above 
that of the sum of the salt and water. The most remarkable feature is 
that of the iodates. The displacement of the saturated solution of caesium 
iodate is only a trifle, 0*79, less than that of the sum of its constituents; 
in the case of rubidium iodate it is 10*03 grams, and in that of potassium 
iodate it is 19*26 grams less. 
It was pointed out in the paper in the American Journal of Science 
above quoted that in the case of the salts of the Ennead MR the crystallisa- 
tion of the potassium and rubidium salts must be hindered by increased 
pressure, while that of caesium salts must be helped by the same agency. 
In the case of the salts of the Ennead MR0 3 it is only the solution of 
potassium bromate the crystallisation of which would be much helped by 
increase of pressure. Regarding the iodates, we see that the crystallisation 
of the saturated solution of caesium iodate would be but little influenced 
by change of pressure, whereas the crystallisation of the rubidium salt, 
and still more that of the potassium salt, would be very seriously hindered 
by increase of pressure. 
The two Enneads, or the double Ennead (MR, MR0 3 ), offer many points 
of great interest, of which an example is furnished in Table No. 5. It 
