Electrical Conductivity and Fluidity of Solutions. 469 
It is generally admitted that this assumption is illegitimate 
as an assumption, but (at any rate in the case of an infinitely 
rare gas) true in fact. But is Mr. Burbury prepared to 
charge with inconsistency all those that hold these views ? 
It need hardly be said that I am very grateful to Mr. 
Burbury for the kind interest he has always taken in my 
work. Criticism, in particular, is always of special value to 
anyone who, like myself, has not worked at a subject for 
long. But in the present instance, although it is only 
with the greatest diffidence that I have ventured to try to 
maintain my position against Mr. Burbury’s criticism, I 
cannot persuade myself that these criticisms have any true 
foundation. J. H. JEANS. 


LVIIL. The Electrical Conductivity and Fluidity of Solutions. 
By RicwarD Hosxrine, 1851 LHehibition Science Research 
Scholar *. 
| Vee present paper describes experiments carried out in 
the Cavendish Laboratory, Cambridge, during the year 
1903 and the Michaelmas Term 1902; and these experiments 
are the continuation of work performed in the Physical 
Laboratory, Melbourne, and described in the Philosophical 
Magazine for May 1902 +, In a joint paper by Professor 
Thomas R. Lyle and myself. 
One of the main results of the Melbourne work was to 
show that both the Specific Molecuiar Conductivity and the 
Fluidity of the solutions used became zero at the same 
temperature, viz., —35°°5 C. 
This result was based on the form of the curves repre- 
senting the temperature variations of both these quantities 
between 100° C. and 0° C.; but it is interesting to find that 
Kohlrausch f quite independently arrived at the conclusion 
that in the case of dilute aqueous solutions, all conductivities 
would cease at practically the same temperature, viz., 
—39° C. 
Another general result was that the fluidity-concentration 
isothermals and the conductivity-concentration isothermals 
all cut the axis of zero fluidity and conductivity respectively 
at the same point, representing a concentration of 10°74 
normal. It was felt that these, and other conclusions arrived 
* Communicated by Prof. J. J. Thomson, F.R.S. 
+ Phil. Mag. May, 1902, p. 487. 
"4 Saez. Akad. Wiss Berlin, Oct. 31st, 1901. 
