SURFACE TENSION O F URSXYL SALT SOLUTIONS
1227
( 3 3 ) S T R t j m m G , R.:Kgl. Svenska Vetenskapsakad. Handl. [2] 6, 1 (1928). F. T . : Proc. Roy. SOC.(London) A79, 383 (1937). (31) TROTTOS, (35) WARBL-RG, E . , ASD ImfoRI, T . : W e d . Ann. Physik. 27, 481 (1886). IHJIORI, T . : Wied. Ann. Physik. 31, 1014 (1887). (36) WISKELMASS,A , , AND SCHOTT, 0 . :.4nn. physik. Chem. 61, 730 (1894). Cf. MOREY, G . W.: Properties of Glass, Reinhold Publishing Corporation, Ken- P o r k (1938).
T H E SURFACE TENSION AND VISCOSITY OF SOLUTIOKS O F URANYL SALTS W. E. GRANT, IT. J. DARCH, S. T . B O W D E S ,
ASD
W. J. JOSES
Tatern Laboratories, Cnicersity College, C a r d i f , Wales Receiued Soeember 18, 1947
The surface tension of water is increased by a dissolved salt, and Bugliginsky (4) and Quincke (28) have shown that the variation of the surface tension, uc, of a salt solution a t constant temperature with its concentration, c, is well represented by the linear equation u, = ao(1
+ kc)
where u0 denotes the surface tension of the solvent and k is a positive constant. To cover still wider ranges of concentration and other solutes besides salts, Freundlich (I 1) has put forward the exponential formula u, = uo(1
+ k’cn)
where k’ and n are constants dependent on temperature, solute, and solvent, but here IC’ is not necessarily positive. According to Heydweiller (15), however, the surface tension of very dilute solutions of salts does not vary simply linearly with concentration, and Jones and Ray (20) find a minimum capillary rise at about millinormal concentration. The effect of electrolyte on the surface tension of a solvent has been further discussed by several workers (26. 30). The depressions of surface tension observed by Jones and Ray amount only to 0.01 to 0.02 per cent of that of pure water, a difference too slight to be observable by the method of measurement adopted in the present ivork. Dissolved salts generally increase the viscosity of n-ater, but, as Wagner (31) found, the chlorides of potassium, rubidium, cesium, and ammonium, and thallous nitrate have the opposite effect. It was found by Gruneisen (13) that the function ( q c / q o - l ) / c passed through a minimum value at about seminormal concentration whether the salt increased or reduced the viscosity, 7 0 , of the solvent, q , denoting the viscosity of a solution of concentration c. The existence of this effect was confirmed by Jones and Dole (17) and ascribed by them to interionic attraction. Jones and Talley (21) showed that for several salts in
1228
'vv.
E. GRAKT,
w. J.
DARCH,
s.
T. BOWDEN, AND
w. J.
JONES
aqueous solution the variation of viscosity over fairly wide ranges of concentration was given by the relation
where ;1is iz positive conrtant and B is a constant, positive for x salt that increases the viscosity, but negative for a salt that decreases thc viscosity of the solvent. The evaluation of the constant -4 in terms of the ionic conductances a t zero concentration, the dielectric constant and vi,cosity of the solvent, and the temperature has been effected by Falkenhagen, Dole, and Vernon (9, lo), and the general correctness of this expression for -4 and the applicability of the above equation have been confirmed experimentally by a number of investigators (5, 16, 22, 23, 27), though A has been found to be negative for aluminum and nickel chlorides in ethanol by Dolian and Briscoe (7) and for ammonium sulfamate in water by Schmelzle and Westfall (29). Onsager and Fuoss (25) have also discussed the general theory of the interionic effect, and according to Jones and Fornwalt (18) their treatment simplifies to the relation:
2= 70
1
+ A & + H C + DClog c +
The object of the present investigation has been to examine the influence of uranyl salts on the surface tension and viscosity of water and methanol, and to ascertain whether the effects can be formulated in accordance with the abovementioned equations. EXPERIMENTAL
Preparation of materials and solutions UrLtiiyl nitrate hexahydrate of analytical grade was allon-ed to stand under sodium-dried benzene for 24 hr. in order to remove the film of moisture adhering to the crystals; the benzene was decanted and the crystals were freed from benzene by washing with dry petroleum ether; the hexahydrate thus treated had a purity of 99.92 per cent. TTranyl acetate dihydrate had a purity of 99.84 per cent after similar treatment. Anhydrous uranyl acetate was prepared from the dihydrate by entrainment distillation of the water with heptane, and the purity of the salt thus obtained was 99.60 per cent. Anhydrous uranyl nitrate could not be obtained by this method, owing to the occurrence of decomposition with evolution of nitrous fumes. The liquids used in the investigation were subjected to the following purification processes : Water was distilled in an all-glass apparatus with the distillation, condensing, and receiving units sealed to one another to avoid contamination with grease. Benzene was dried over calcium chloride and then distilled from sodium wire. Methanol was obtained in the anhydrous condition by treatment of the liquid with magnesium methoxide prepared in situ (24). Since anhydrous uranyl nitrate .\\-asnot available, measurement3 were carried
1229
hURFACE TESSIOS OF URASTL SALT SOLUTIOBS
out on the hexahydrate in methanol. The low solubility of anhydrous uranyl acetate in water and in methanol limited the investigation to dilute solution, but the solubility of the dihydrate in methanol permitted the examination of a series of these solutions. Each solution was freshly prepared a t 20°C. in a 100cc. flask, care being taken to avoid undue exposure to light; the solution was generally used for the measurement of density, surface tension, and viscosity over the entire temperature range of the experiments. Densities mere determined by means of pycnometers with capacities of 10 cc. and 25 cc., respectively, using standardized weights and applying the usual buoyancy corrections. Surface tension and viscosity determinations 'l'hc measurement of the surface tension of the pure liquids and solutions was carried out by the differential bubbling method, using the form of instrument described by Bowlen and Butler (3). The apparatus \vas immersed in a thermostat (containing water or a solution of calcium chloride) provided with a bimetallic thermoregulator in circuit with a hot-wire vacuum switch which gave TABLE 1 I _
0°C.
I
20T
25°C.
30°C.
35'C.
1
40°C.
50°C.
I
fd
I?
JIatliiitiol
1?
0 9993 i5 8 1 71r+ 0 8098 24 7 0 601
I
0 9983 72 6 1.006
0.9965 i1.5 0.893
0.9954 70.5 0,800
0.9533 65.9 0.469
0 7916 22 i 0 5s9
0. X i
0.;523 21.8 0.512
0 753i 19.0 0.346
0,551
103°C.
-
-lI \Inter < u
80".
60'C.
0.9718 62.2
-
0.9584
69.2
_--
a m:isiixium tolerance of 0.04"C. over the temperature range of the experiments.
The instrument was calibrated with dry benzene, for which the surface tension a t 20°C. \vas taken as 29.1 dynes per centimeter. For the viscosity measurements an all-glass viscometer \\as constructed according to tlie specifications of the I3ritish Engineering Standards Association, and the tlesign incorporated the recommendations made by Barr (1). The instrument \Y;I+ provided nith a ground-glass stopper which had a by-pass to the capillarJ- limb and also an orifice io bring the two limbs into communication so that Ihr determination could be carried out in a dust-free atmosphere in a closed system. To avoid vapor losbeb the bulb of the viscometer was filled by applying pressure to the receiving limb. Times of flow were observed by means of a stopwatch which \\.as periodically calibrated against a standard chronometer. The viscometer was set vertically in :I thermostat whose temperature was controlled t o 0.005"C. by a Sunviv electronic relay in conjunction with a tolueneiiiercury regulator provided with a bimetallic proportionating head. In vien- of the differences of opinion ( 2 , 8, 19) which still prevail concerning the form and magnitude of the correction to be applied to viscosity measurements
TABLE 2 Uranyl nitrate hexahydrate i n water TEMPERATURE
c
I
d
I -~
"C.
'
0.2291 1.0740 0.2286 1 1.0714 0.2283 1.0703 0.2280 1.0687 0.2277 1 ,0671 0.2273 1.0651 0.2262 1.0609 0.2253 1.0559 0.2230 1.0457 0.2201 1.0315
0 20 25 30 35 40 50 60 80 100
0.1529
0 20 25 30 35 40 50 60 80 100
0.4127 0.4112 0.4107 0.4102 0.4094 0.4088 0.4071 0.4053 0.4019 0.3966
1.1328 1.1291 1.1275 1.1260 1.1240 1.1219 1.1175 1.1124 1.1026 1.0889
76.6 73.4 72.7 72.0 71.3 70.4 69.0 67.5 63.6 60.6
2.19 1.22 1.09 0.974 0.880 0.794 0.668 0.568
0.4842 0.4828 0.4821 0.4815 0.4804 0.4800 0.4777 0.4755
1.1575 1.1540 1.1522 1.1506 1.1488 1.1477 1,1423 1.1369
0 20 25 30 35 40 50 60 80 100
0.6250 0.6219 0.6210 0.6201 0.6191 0.6181 0.6158 0.6131 0.6074 0.5995
1.1985 1.1920 1.1903 1.1886 1.1867 1.1847 1.1800 1.1748 1.1642 1.1492
76.8 73.7 73.0 72.2 71.5 70.6 69.2 67.8 64.2 61.0
2.43 1.33 1.22 1.09 0.978 0.892 0.745 0.632
0.8316 0.8271 0.8260 0.8247 0.8231 0.8215 0.8181 0.8145 0.8063 0.7980
1.2701 1.2634 1.2615 1.2596 1.2570 1.2546 1.2495 1.2440 1.2314 1.218i
0.1523 0.1521
1.0509
~
i 1.0473
1.90
1.0459
0.943 0.844
0.1515 1.0420 0.1507 I 1.0365 0.1501 1.0324
0.691 0.580 0.492
i
I
'
____
76.4 73.3 72.4 71.6 70.6 69.8 68.5 66.9 63.2 59.9
'
1.98 1.11 0.989 0.884 0.796 0.726 0.603 0.514
2.26 1.28 1.14 1.02 0.915 0.832 0.696 0.587
~
1
1 77. 74.6 73.9 73.4 72.7 71.8 70.3 69.0 65.0 61.9
, I
TABLE 3 Cranql acetate d i h y d r a t e i n ?cuter TEMPERATURE
1
1
d
C
-1I
"C.
0 20 25 30 35 40 50 60 80 100
0.02391 0.02383 0.02380 0.02377 0.02374 0.02370 0.02360 0.02348 0.02322 0.02288
I ~
j 1
I
'I I
1.0079 1.0048 1.0032 1.0019 1.0009 0.9987 0.9947 0.9900 0.9788 0.9642 1230
I
I I
1 I I
U
75.0 71.5 70.6 69.7 68 7 68.2 66.7 65.0 61.4 58 6
I1
1 I
I
I
I
11
1.77 0.992 0.879 0,789 0.663 0. 0.463
x:!
1231
SURFACE T E N S I O S O F URdXYL SALT SOLUTIONS
TABLE 4 Uranyl nitraie hexahydrale and uranyl acetate dihydrate in water CE YPLR \TTRE
1
"c
1-
20 25 30 35 40 50 60 80 100
I
I
I I
c (SITRATE)
d
c (ACETATEI
__
0.02324 0.02320 0.02318 0.02314 0.02310 0.02301 0.02291 0.02267 0.02232
0,1977 0.1974 0.1972 0.1969 0.1965 0.1958 0.1949 0.1929 0.1900
72.5 71.6 71.1 70.2 69.0 67.2 66.2 62.9 59.4
1.0678 1.0664 1.0650 1.0633 1.0614 1.0573 1.0523 1.0411 1.0256
TABLE 5 7-ranyl nitrate hexahydrate in ?nethano1 TEMPERA-
TURE
/I
d
v
c
0.950 0.665 0.616 0.572 0.534 0.496 0.431 0.378
0.2043 0.1999 0.1987 0.1976 0.1965 0.1954 0.1932 0.1911
0.8878 0.8686 0.8636 0.8587 0.8539 0.8491 0.8395 0.8302
' 25.5 23.7 23.2 22.8 22.3 21.9 21.1 20.2
1.10 0.778 0.714 0.659 0.609 0.567 0.489 0.428
0.3947 0.3865 0.3845 0.3824 0.3805 0.3784 0.3743 0.3701
0.9602 0.9404 0.9356 0,9307 0.9258 0.9206 0.9107 0.9007
26.8 24.9 24.4 23.9 23.6 23.2 22.2 21.2
1.45 1.01 0.922 0.843 0.775 0.715 0.606 0.519
"C.
0 20 25 30 35 40 50 60
0.10050 0.09826 0.09770 0.09718 0.09658 0.09603 0.09493 0.09378
0.8482 0.8294 0.8247 0.8204 0.8153 0.8106 0.8013 0.7916
25.0 23.2 22.8 22.2 21.7 21.3 20.4 19.5
0 20 25 30 35 40 50 60
0,2974 0.2931 0.2916 0.2899 0.2886 0.2870 0.2837 0,2806
0.9229 0.9033 0.8984 0.8932 0.8890 0.8841 0.8740 0.8646
26.2 24.3 23.9 23.4 22.9 22.5 21.7 20.7
1.27 0.883 0.812 0.766 0.709 0.648 0.554 0.480
0 20 25 30 35
0.5128 0.5023 0.4997 0.4972 0.4945 0.4922 0.4868 0.4816
1 .0015 0.9811 0.9759 0.9709 0.9658 0.9614 0.9508 0.9408
27.4 25.6 25.1 24.7 24.3 23.9 23.0
1.75 1.19 1.08 1 0.981 0.893 , 0.817 0.692
40
50 60
22.1
'
0.5%
for the influence of surface tension, the values of the viscosity given in the present work have not been corrected for this effect. The values found for the density, surface tension, and viscosity of the pure
1232
W. E. GR4NT, TV. J. DARCH, S. T. B O W D E S , BND W. J. JONES
solvents are contained in table I , where d is the density in grams per cubic centimeter, u is the surface tension in dynes per centimeter, and 7 is the viscosity in centipoises. The results for the solutions are listed in tables 2 to 7 , where c is the concentration of the dissolved compound in moles per liter of solution. TABLE 6 Uranyl acetate dihydrate in methanol TEYPERA-
d
C
TUPS
'1
C
_-
__--
__- ___.
-
"C.
0.03248 0.03178 , 0.03161 0.03142 0.03124 0.03105 0.03067 0 .03028
0 20 25 30 35 40 50 60 0
,
0.8199 0.8023 0.7980 0.7932 0.7886 0.7838 0.7743 0 . 7645
0.1446
'
,
0,8558
1 0.8366
' 0.8318
. 0.13S2
35 40 50 60
'
0.1374 0.1358 0.1342
1 1
1 1
0 . 8269 0.8222 0.8174 0.8078 0.7980
l l
'
I
0.07194 0.07036 0.06995 0.06956 .0.06915 0.06876 0.06792 0.06708
23.0 22.4 21.9 21.5 21.0 20 2 19.3 25.0 23.1 22.6 22.1 21.6 21.2 20.3 19.7
,
I
0.910 0.647 0 600 0.559 0.521 0.485 0.423 0.378
0,2147 0.2100 0.2088 0.2077 0.2065 0.2053 0.2031 0.2005
0.8325 0.8096 0.8050 0.8002 0.7956 0,7859 0.7762
24.9 23.0 22.5 21.9 21.5 21.0 20 .o 19.4
0 . b25 0.603 0,561 0.523 0.188 0.456 0.401 0.353
0.8772 0.8580 0.8533 0.8484 0.8431 0.8389 0.8294 0.8194
25.2 23.1 22.6 22.2 21.7 21.3 20.5 19.9
0.965 0.686 0.635 0.592 0.550 0.504 0.447 0.392
' 0.8141
',
I
1 I
TABLE 7
TEMPEXAIUXR
"C.
I
'
_____ __
- ._
I
d
0
_I_-
~
_-
._I
7 --
I
DISCUSSION O F RESULTS
The present results show that while uranyl nitrate increases the surface tension of water, uranyl acetate has the opposite effect. That the relative magnitudes of these two opposing effects vary but little with change of temperature is proved by the data given in table 4 for a solution which n-as prepared a t 20°C. to contain
1233
SCRFACE TENSION O F UR4NYL SALT SOLUTIOXS
TABLE 8 Application of Rugliginsky and Freundlich equations C
1
I
AuB
1
AUF
hobsd.
1
1
~
C
I
AUB
AUF
1
AUobad.
Uranyl nitrate hexahydrate in water
0.6250 0.8316
i
1.1 1.6
1.1 1.6
'
I
X'
Temperature, 4OOC.; k = 0 01200; 0 04053: YZ = 0 9656 O 2273 0 1088
0.2230 0.4019 0,6074 ( J , 8062
I
i '
[
0 7 1 2
0.8 1 .I 2.2
~
0 T 1 2
1
0.S 1.4
1
.
-.
E
~~
I
02253 0 4053
1 4
::: 1
2.0 2.!)
~
~
..
1.9
1
1.4 1.9
1.1 1.9
Temperature, 60'C.; k = k' = 0 05711; n = 1 000
=
-
1
2.2 2.9
2.9
0.4112 0.6219 0.8271
1.0 1.8
~
0 0 l i
1
0.2201 0.3966 0.5995 0.i980
1
~
i
,
0.7 1.3 2.0 2.6
I
! , ~
j
0 9 15
0.7 1.3 2.0 2.6
1
~
-
10 1 7
1.8 2.6
. ~ ~ ~_ . ~~
~
Lraiiyl nitrate liesaliydrate in methanol Temperature, 0°C.; k = 0 2087; k' = 0.2534;n = 1.171 0 1003 0 2043 0 2971 0 3947 0.5128
,
0 5
0 4
1 1 1 5,
I 0
0 8
20 2 G
2 t
2 1
Temperature, 20°C.; 12 = 0.2404; k' = 0 . 3 0 2 8 ; ~=~1.203
0 5
0 0'3826
0 3
1 6
Temperature, 40°C ; A = 0 2636; k' = 0 3422;n = I 20-1 __ -~ 0 09MR 0 .5 0 1 0.4 0.1954 1 1 1 0 I .o ~
0 3865
Trmperature, 60°C.; k = 0.3225; k' = 0 38'39;n = 1 203 - - -
0 09378 0.1911
I
0.6 1 2
0.4 1.0
I
i
0.4 1.2
m. E.
1234
s. T. IKIWDES,
J. DIRCH,
GRANT, T.-I
Temperature, 20"C., X = 0 07341; k' = 0 08095; I L = 1 043
Temperature, 0°C.; X = 0.1014; A ' = 0 1035;n = I 005 0.03248 0.07194 0.1446
I
0.1 0.2 0.4
1
0.1 0.2 0.4
AND if-. J. JONES
1
0.2 0. 3
0.03178 0.07036 0.1406
,
0.1 0. I 0.2
0.1 0.1 0.2
0.4 Temperature, 40°C ; A = 0.08762; h' = 0 08517,n = 0 974
___~_
1
__
0.03105 0 06876 0.1374 0.2053 --
~
-
0 0 0 0
1 1 3 4
0 0 0 0
0.1 0.1 0.3 0.4
1 1
3 4
__
1 -
-
1
- -
' ~
0.3 0.3 0.4 0.4
Temperature, 60°C.; k = 0.1820; k' = 0.1910;n= 1.023 __ 0.03028 0 06708 0.1342 0.2005 I - . ___ -
0.1 0.2
0.5 0.7
~
0.1 0.2 0.5 0.7
~
I
0 3 0 4 0.7 0.8 ~-
99.33 g. of the nitrate hexahydrate and 9.85s g. of the acetate dihydrate per liter so that the surface activities of the tn-o solutes should annul each other. Comparison of table 4 with table 1 shonr4 that the surface tension of the solution containing the t u o solutes keeps ('lobe to that of pure water over the entire range of temperature. In methanol, however, the surface tension is raised by uranyl nitrate hexahydrate and by uranyl acetate dihydrate. The applicability of the Bugliginsky and Freundlich equations is shown in table S, where l u B repitsents the difference between the surface tension of the solution and that of the solvent a s calculated from the Bugliginsky equation, i l u F the difference given hy the Freundlicli relation, and j.uobsd. the experimentally observed value of uL - u,,. Except for the system uranyl nitrate hexahydrate-methanol, I L so closely approaches unity that the tivo equations are practically identical and each ielation giveh equally good correspondence between the observed and calculated values of l u . For the aforementioned system, however, iihere the valutl of 71 is about 1.2, the Fieundlich equation i.; in better accord with the experimental results. It will tie noticed that the conbtant 1;' of this equation for a given system is a non-linear function of temperature, and may attain a maximum or a minimum according to the nature of the solution. The influence of uranyl salt3 on the viscoaity of the liquids is seen by comparing the data in tables 2 t o 7 with those in table 1. Xt the concentrations examined it is evident that uranyl nitrate liexahydritte increasw the viscosity of water, ant1 that uranyl acetate dihydrate has little effect. The viscosity of methanol is ixiyed by the nitrate hexahydrate and the aretate dihydrate, but is only slightly influenced by the anhydrous acetate The ronhtantb 017 tained on applying the Jones-Talky cquation to the results giren in tables 2 to G are listed in table 9. In this table are also given, for three representative solution., the value.: of the viscosity, -qrJlcd , calculated using the
1235
SURFACE TESSIOS O F URANYL SALT SOLUTIOXS
above constants, and the differences, Aq, between these values and the observed viscosities; these three solutions were those for which the molar concentrations at 0°C. were, respectively, 0.4127 of uranyl nitrate hexahydrate in n-ater, 0.2043 of uranyl nitrate hexahydrate in methanol, and 0.1446 of uranyl acetate dihydrate in methanol. For the range of concentration investigated the results accord satisfactorily with equations of the Jones-Talley type. The fact that the constant A is not positive for aqueous solutions of uranyl nitrate may be due to a variety of causes, for the ionization of uranyl salts in water is known to involve formation of complex ions which undergo change of constitution with dilution of the solution T.4BLE 9 Constants a n d L iscosities calculated f r o m Jones-Tulley equation
I
O'C
I
20°C
25T.
1
35°C
30°C
, '
4OT.
50°C
600C
Uranyl nitrate hesahydrate in water
-
'
- A . . . . . . . . ) 0.141 B . . . . . . . I 0.7515 qenlcd.. . . . 1 Aq . . . . . . . . . ~
I
I
2.19 0.00
~
I
0.142 0.7251 1.21 0.01
~
I
I
__
0.180 0.8266 1.09 0.00
~
0.172 0.8054 0.976 0.002
~
.____
0.200 I 0.180 I 0.8379 0.8100 0.880 0.799 j 0.000 0.005
~
~
~
i
0.180 0.7938 0.665 0.003
1
I
1 ___. ___
0.155 0.7727 0.570 0.002
Uranyl nitrate hexahydrate in methanol
- A ........ B........
0.320 2.486 Vcalcd . . . . . . . , 1.09 Aq , . . . . . . . 0.01
' ~
.I
~
I
0.407 0.378 2.509 1 2 . 3 9 7 0.778 0.720 0.000 0.006
0.3i2 0.312 2.346 2.203 0 . ~ ~i 50.618 0.006 0.009 ,
1
~
~
~
I
0.340 2.183 I 0.568 0.001 ~
0.271 1.893 0.487 0.002
1
I
0.260 1.812 0.427 0.001
Uranyl acetate dihydrate in methanol
- A . . . . . . . . I 0.330 B , . . . . . . . 1.746
1
Vealod.. . .
... Av.,. . . . .
~
0.903 0.007
~
' ~
0.294 1.465 0.646 0.001
1 ~
~
0.300 1.435 0.600 0.000 ,
0.252 1.317 0.558 1 0.001 ,
~
0.262 1.336 0.519 0.002
__
~
0.195 1.156 0.484 0.001
i ~
I
I
~ ~ _ _ _ _ _ _ ~
0.220 i.211 0.423 0.000
I
I ~
0.150 1.060 0.376 0.002
______
(6, 12, 14); further, the negativity of this constant for solutions of the hydrates in methanol may be due partly t o the effect of the water. S17JlM\IART
The surface tension and viscosity of solutions of uranyl nitrate hesahydrate, uranyl acetate dihydrate, and anhydrous uranyl acetate in ]rater and in methanol have been measured a t a series of temperatures from 0°C. t o the neighborhood of the boiling point of the solrent. The surface tension of water is Iaised by uranyl nitrate but is lowered by uranyl acetate. The surface tension of methanol is raised by uranyl nitrate heiahydrate, by uranyl acetate dihydrate, and slightly by anhydrous uranyl acetate. The Bugliginsky equation applies to aqiieous solutions of uranyl nitrate and
1236
TI-. E. GRANT, TT. J. DARCH, S. '1'. 13O\VDEK, A K D IV. J. JOKES
methanol solutions of uranyl acetate dihydrate, but the Freundlich relation is in better accord mit'h the results for methanol solutions of uranyl nitrate hexahydrate. The viscosity of water is increased by uranyl nitrat'e, but is little influenced by uranyl acetate. Vranjd nitrate hexahydrate and uranyl acetate dihydrate increase the viscusit,y of methanol, but t'he anliydrous acetate has only a slight effect. Equations of the Jones-Talley type are found to be applicable over the range of concentrat'ions studied, but here the const,ants are purely empirical, calculation by means of the Falkenhagen-Dole-Vernon expressions not being possible even for t'he aqueous solutions, owing to the complexitmyof the ionization and t'he incidence of hydrolytic reactions. REFEREKCES (11 UIRR, C i . ::I .\lharrdl. ;,!iysik.-tisc.ti. Keiciiuiiristalt 4, 239 (1905). (141 C ; ~ . I T E R , H . : Bull. soc. chiin. Fraricc 1947.64. (1:) I ~ F : P D W I ~ T-1.: I . I1.iEi 1R i. , -sik i4! 33, 1.45 (191U). (161 ,JOSCS.( i . . AS11 ( ' H R I F T I . 1 SI.:.J. .11ii. ('tiem. S O C .66, 1017 (1944). . h i . ( 2 ' l l v l l i . SOC.61, 2U;iO (19%). (1;) t J o ~( i . ~ . .%SI) ~ . 11(11,i.:.~\[. I 1s) ,JOSES. C;., 6x1)I'oKs\\ {I,','. 14. ,I.: J . .\!il. ( . ' l \ t s i t l . SOC.67,2 ) 4 1 ( , l ( I % n .
. A n . ( ' h i l i i i . SOC.67, ! ) s i (1(3:35i;69, 18; (1037); 63, 288, (201 .lo!;Es, c j . , . i l l ) I { . \ Y . \\'. .\ 3263 (ICJ-11); G&, 2744 ( 1 9 4 ~~ , IY
