474 
PROFESSORS A. W. REINOLD AND A. W. RUCKER ON 
£ ]8 10 8 =G701, spec. grav. at 18 C = 1 • 1799 
& 18 10 8 =6911 „ „ =1-2201 
where k 18 is the conductivity at 18° C. referred to that of mercury at 0° as unity. 
Assuming that, between the two specific gravities given above, the change in con¬ 
ductivity is proportional to the change in specific gravity, we have 
hence 
& lg 10 8 =6802, for sulphuric acid of spec. grav. 1-1993 at 18°. 
p = —X specific resistance of mercury 
™18 
=e^ x - 970=1 ' 4260 - 
lire value assumed here for the specific resistance of mercury, viz. : -970, is that given 
by Kohlrausch himself. Matthiessen gives 0 - 9619 (Everett’s ‘Physical Units’), 
but it was thought desirable in transforming Kohlrausch’s numbers for liquid con¬ 
ductivities to make use of the specific resistance of mercury which he had himself 
obtained. 
II. Sulphuric acid, spec. grav. at 18" = 1 "4119, computed from measurements made at 
12°-5 and 16°-5. 
The resistance was measured at four temperatures, and from the curve so obtained 
the specific resistance at 18° was deduced =2"001. 
Kohlrausch gives 
whence 
&i 8 10 8 =5112, spec. grav. at 18°=1"3946 
& 18 10 8 = 3494 „ „ =1-5014 
& 1S 10 8 =4849"9, for spec. grav. 1-4119 
_ 10 8 x-97 
' • P ~ 4849-9 
2-000 
III. Sulphuric acid, spec. grav. at 18°= 1-611. 
The resistance was measured at 17°"56 and at 22°*25. Specific resistance at 18° 
deduced =4 - 725. 
Kohlrausch gives 
& 18 10 8 = 2554, spec. grav. = 1 *5707 
£ lg 10 8 =1823 „ =1-6315 
whence 
& 18 10 8 =2069‘5 for spec. grav. 1*611. 
.-. p=4-687. 
