1889. ] Lowering of the Freezing Point of Tin. 367 
the metals, a known weight of tin (from 200 to 400 grams) was 
introduced together with some solid paraffin to prevent oxidation. 
The block was then heated by means of a Bunsen; and a 
delicate thermometer, on which ;1, ths of a degree centigrade by 
aid of a reading telescope could be estimated, was inserted; the 
molten tin was continually stirred by means of a plunging annular 
stirrer worked by a water motor. The stirring was continued 
during the whole time the tin cooled, and the highest temperature 
ever reached by the thermometer after the surfusion commenced 
was taken to be the exact temperature of solidification. The 
thermometers used in the earlier experiments were found to be 
quite unsuitable, as the high temperatures at which they were 
kept for many hours caused a perceptible rise in the zero point 
during the course of an experiment. 
By using the fixed zero thermometers of Mr J. J. Hicks of 
Hatton Garden this difficulty was overcome, no shift in the zero 
being perceptible after many weeks of use. 
With the single exception of antimony all the metals which 
we have at present been able to dissolve in tin cause a lowering 
in the freezing point, and further for the same metal this fall is 
proportional to the weight of the metal in solution and inversely 
as the atomic weight. 
OBSERVED LOWERING OF FREEZING POINT OF TIN CAUSED BY 
ADDING ONE ATOMIC PROPORTION OF METAL TO ONE HUN- 
DRED ATOMIC PROPORTIONS OF TIN (i.e. 11800). 
ASruSe ae Atomic | Observed | 
el weight. | lowering. SSUDEH SE 
Sodium 96 23 2°5. | soluble with difficulty. 
Aluminium GOO Mane 14 different samples of 
| Aluminium. 
Copper 1050 63 2°47 | 
Zine 412 |. 65 2°53 
Silver 954 | 108 2°67 very pure precipitated 
| Ag. 
Cadmium 320 | 112 | 2-16 ' 
| Gold LTS Oe elas, 2°65 very soluble. 
Mercury — 38:5 | 200 2°3 
Lead 335 | 208 2-22 
Bismuth 265 0 210 2-26 
3°86 
Antimony 210 120 | to | rise, 
| 2°82 | 
