132 ON THE CALCULATION OF THE CONDUCTIVITY OF 
The following table contains in columns 1 and 2 the concen- 
trations of the solutions of hydrochloric acid and sodium 
chloride which were mixed, and in column 7 the measured 
conductivities of the mixtures, obtained by graphical interpola- 
tion from the above observations. The 3rd, 4th and 5th columns 
give the common concentration of ions and the respective dilu- 
tions of the electrolytes, in the mixture, as determined by Prof. 
MacGregor’s graphical process. The 6th column gives the cal- 
culated values of the conductivity, and the 8th the excesses of 
the calculated over the observed values expressed as percentages. 
Constituent Solu- : Pontinehivity 
ions. aaa F etivity 
Cuncentcaiion Wwoncenit: Palee the of Mixture, 
(Gramme-mole- frahionlat as . «10° Differ- 
cules per litre.) Tons ences 
in the per cent. 
OIC | a 
= = Caleu- Mea 
HCl. Na Cl HCl. Na Cl lated. | sured 
2 E 2.02 1.272 539 .451 | 3020 3008 +0.4 
2.5 5 1.392 592 .398 | 3489.5 | 3456 +1.0 
3.0 e 1.485 636 .oot | 3885 3888 —0.08 
as) os 1.570 668 B22 4233.5 4260 -0.6 
4.0 ee 1.665 700 .290 | 4622.3 | 4580 +1.0 
4.5 ss 1.740 726 . 264 4944 4880 +1.3 
1 1.04 . 144. 1.031 .892 1751 1752 — (0.005 
1.5 A .916 1.215 .708 2373 2332 +1.7 
2.0 ot 1.062 1.345 | .578 | 2928.3 | 2900 +0.9 
2.5 es 1.196 1.431 492 | 3428.5! 3398 +0.9 
3.0 fs 1.324 1.495 .428 | 3906 3872 +0.9 
3.5 WG 1.440 Weaisy, || gare} 4340.7 4316 +0.6 
4.0 Le 1.538 1.585 888 4715 4700 +0.3 
4.5 | es 1.628 1.616 SU |) ORS 5036 +0.4 
A 607 392 1.450 1.844 | 829.8 $38 -1.0 
35) = .436 1.636 1.656 983.4 976 +0.8 
6 fe 474 1.794 | 1500 {1125.5 1116 +0.8 
al ‘ .508 p27, 1) ikesyea PAs. 1250 +0.4 
8 £é 544 2.022 | 1.272 (1384.7 1388 -0.2 
9 § 582 2.121 1.173 |1524.6 1525 — 0.025 
ILO) ay .620 2.195 | 1.099 |1658.6 1656 +0.16 
Ill ‘ 655 2.267 1.027 |1787.6 1784 +0.2 
1.2 es .692 2.322 .972 {1917.1 1913 +0.2 
It will be seen that in the series of weakest solutions, the 
differences between calculated and observed values are of such 
