APPLICATIONS OF THE VISCOMETRIC METHOD 291

V;™Jicentration up to a concentration of 0.175 but this and the
remaining observations are reproduced by the formula

<p = 207.7 - 306.76*r (115)

Neither formula gives the true fluidity of water at 70° (245.7)
when the weight concentration bw of palmitate is zero, and we
obtain two different concentrations corresponding to zero fluidity,
using the two formulas, of 0.477 and 0.677 respectively, which are
difficult to interpret.

TABLE LXXIII.—FLUIDITIES OF AQUEOUS SOLUTIONS OF SODIUM PALMITATE
AT 70°C (AFTEB FARROW)

Concentration by weight
Viscosity, observed
Fluidity, observed
Fluidity, calculated

0.026
0.00438
228 .
227

0.064
0.00485
206
208

0.105 0.131
0.00530 0.00579
189 173
188 174
Formula I

0.141
0.00592
169
169

0.175
0.00647
155
152

0.175
0.00647
155
154

0.187
0.00665
150-
150

0,232
0.00743
135
136

0.283
0.00793
126
121

0.287
0.00866
115
120

0,293
0.00847
118
118
Formula II

0.302
0.00886
113
115

0.329
0.00949
105
107

0.380
0.01113
90
91

0.451
0.01363
73
69

0.499
0.01800
56
55

W. L. Hyden has made a study of the plasticity of solutions
of nitrocellulose in acetone, but the results have not yet been
published. He finds that these colloidal solutions differ from
the suspensions of clay et cet. studied by Durham in that the
concentration of zero fluidity at a very low shear, i.e., the transi-
tion from viscous to plastic flow, occurs in an extraordinarily low
concentration of colloid, certainly less than one per cent.
Since the apparent viscosity of such colloid solutions is depen-