1912-13.] Compressibilities of Solutions of Inorganic Salts. 287 
volume of the solution at atmospheric pressure occupies under an external 
pressure AK. 
Both AK and v a k depend on the concentration ; v aK being obtained 
from the equation 
1 - A log 
B+ AK 
It is clear that when there is no salt in solution 
A K = 0 and v Ak = 1 . 
Hence formula (2) becomes 
_i d l- A 
v 0 dp B ’ 
which agrees with (1). 
Taking, then, equation (2), I substituted the observed values of 
the compressibility on the left-hand side, and found by a process of 
trial and error the values for AK which gave most consistent results. 
I found that in general it was possible to find values for AK which 
satisfied equation (2) within certain limits. I have included in the 
following table the values of AK found in this way for each solution, and 
also side by side the observed and the calculated value of the compressi- 
bility. The symbols have the following meaning : — 
A is the equivalent weight of the substance. 
c is the concentration (grams in 100 grams water). 
S is density relative to water at same temperature. 
p is the pressure in atmospheres. 
1 ctu « 
/3 f is the value of — found for pressure p. 
v q dp 
/3 C is the value of same calculated from formula (2). 
Na 2 C0 3 . A 1 = 53-06. 
p 
fa x 10 7 
fa x 10 7 
aK 
52 
419 
424 
215 
398 
402 
380 
426 
383 
377 
770 
341 
342 
36 
461 
459 
176 
441 
436 
335 
424 
414 
120 
548 
383 
386 
875 
360 
350 
V 
| fax 10 7 
fi c X 10 7 
aK 
aK 
c 
48 
470 
468 
155 
447 
448 
300 
420 
419 
80 
215 
600 
388 
386 
800 
371 
363 
50 
468 
467 
160 
285 
447 
437 
448 
429 
70 
376 
430 
424 
408 1 
Particulars 
concerning 
Solution. 
3-59 
S= 1-03400 
c = -910 
v 0 = 46-10 
S= 1-00957 
aK 
106 
132 
Particulars 
concerning 
Solution. 
c= -371 
^0 = 46-10 
S= 1-00395 
c = -186 
v 0 = 45-90 
S= 1*00198 
