and its bearing on the Nature of Solutions. 



499 



Depression of the Freezing-point of Water produced by the 

 addition of Sulphuric Acid. 



Per cent. H 2 S0 4 . 



Mols. H o S0 4 to 

 100 H 2 0. 



F.-P. 



Molecular 

 depression. 



0-068 



00125 



- 0-0369 



2-95* 



0-3618 



00667 



- 0-1580 



2-37 



0-44 



00811 



- 1874 



2-31 



1057 



01961 



- 0-4214 



215 



2-500 



0-4708 



- 0-9825 



209 



4021 



0-7692 



- 1-600 



2-08 



6000 



1-1855 



- 2-520 



215 



8-585 



1-724 



- 3-456 



2-00 



18-492 



4-167 



-11-83 



2-84 



29-526 



7-692 



-34-00 



3-74 



37-701 



11111 



-72-63 



6-54 



The depression with solutions weaker than H 2 S0 4 to 100 

 H 2 varies between 2 o, 08 and 2°*95, 42 per cent., and even be- 

 tween 0'44 and per cent, it varies from 2 0, 31 to 2°*95, 

 a variation of 28 per cent., numbers which can give no grounds 

 whatever for the statement that the depression, even with these 

 very weak solutions, is independent of the strength. 



The only other determinations which, so far as I know, 

 exist with solutions containing less than one dissolved mole- 

 cule to 100 of the solvent, are those of Heycock and Neville 

 (loc. sup. cit.) with certain alloys. Selections from those 

 series which were most fully investigated supply the following 

 data : — 



Solvent. 



Dissolved substance. 



Molecular depression. 



100 Na 



»» 



)> 



0114Au 

 0-296 „ 

 0-966 „ 



0-097 Cd 

 0391 „ 



0-648 „ 



o 

 5-45 

 4-74 

 454 



392 

 3-71 



3-17t 



* With still weaker solutions the molecular depression is somewhat 

 greater : with a 0-005 per cent, solution (-0009 H 2 S0 4 to 100H 2 O) the 

 value found was 3°-4, but the total depression here is so small that I have 

 not included it or similar values in the table. 



t With thallium, mercury, sodium, and indium, the depression was 

 more constant, but the data were less complete. 



