1887.] Mr J. Y. Buchanan on Ice and Brines. 133 
table are given the means of the temperature at which ice began to 
form in the original solution, and that of the liquid when the sample 
of brine was taken, and the means of the chlorine found in the 
original solution and in the brine sample : — 
Mean freezing temperature, . -1°*875 C. - 1°*63 - 1°*30 — 0°*975j ; 
Mean per cent. Cl., . . 3 *87 1*60 1*30 0*98 
It will he seen that, in the dilute solutions experimented with, 
the percentage of chlorine expresses, in terms of the Centigrade 
scale, the lowering of the freezing-point of the solution. 
Sea- Water. — Similar experiments were made with sea- water of 
different degrees of concentration. In sea-water from the Birth of 
Clyde containing 1*84 per cent, of chlorine, ice forms at - 1°*9 C. 
The following results are from means of close-agreeing results : — 
o o o o 
Freezing temperature, . - 2*0 - 1 *5 - 1 '0 - 0 ‘5 
Per cent, chlorine, . 1*94 1*445 0*963 0*475 
Difference, . . . 0*06 0*055 0*037 0 025 
Sea-water resembles a chloride of sodium solution containing 
the same percentage of chlorine, and the resemblance is closer the 
greater the dilution. When the beaker was removed from the 
freezing-hath, the temperature rose during melting as it had fallen 
during freezing. In these experiments, which had for their object 
the determination of the temperature at which the crystals melted, 
as well as that at which they began to form in the water, it was 
impossible to remove a sample for analysis large enough to enable 
the sulphuric acid to he determined in it. 
For this purpose a series of observations were made, using 
quantities of 300 grammes of sea-water. Freezing was continued 
usually until the temperature had fallen 0°*3 C. below that at which 
crystals began to form. The mother-liquor was then separated from 
the crystals by means of a large pipette with fine orifice, before 
removing the beaker from the freezing hath. The magma of 
crystals was then brought rapidly on a filter and drained by means 
of the jet pump. The ice, thus drained, was then melted, and the 
three fractions were analysed. In the following table (I.) the 
results of four experiments are given. In the one column (W) will 
be found the weight of the original water taken and of the fractions 
into which it was split on freezing ; in the other (R) will be found 
