4G2 
MESSRS. T. E. THORPE AND J. W. RODGER ON THE RELATIONS 
As the hydrocarbon readily absorbs oxygen, which transforms it into a liquid of 
syrup 3 ^ consistence and higher boiling-point, it was carefully redistilled in a current of 
dry carbon dioxide. The greater portion boiled regularly between 35°‘38 and 36°'03. 
Bar. 758‘5 millims. Corrected and reduced b.p. = 35°'76. 
The observations for viscosity gave :— 
Left limb. 
Rio-ht limb. 
0 
Temp. 
Press. 
Corr. 
'/• 
Temp. 
Press. 
0 ■ 
0 
']■ 
0-36 
101-71 
-000075 
-002587 
0°34 
101-73 
-000075 
•002591 
5-68 
101-37 
-000078 
-002456 
5-56 
101-40 
-000078 
•002462 
10-27 
101-24 
-000080 
-002359 
10-27 
101-18 
-000u80 
•002356 
15-31 
101-21 
-000084 
-002248 
15-.35 
101-16 
-000083 
-002-250 
20-40 
101-22 
-000087 
-002145 
20-42 
101-19 
-000087 
•002149 
25-27 
101-21 
-000089 
-00-2060 
25-24 
101.16 . 
-000089 
•002060 
28-95 
101-21 
-000092 
-001993 
28-94 
101-14 
-000091 
•001998 
32-02 
101-22 
-000093 
-001944 
.32-03 
101-15 
-000093 
•001945 
29-93 
129-98 
-000117 
-001984 
29-94 
129-90 
•000117 
•001986 
As isoprene is one of the least viscous of the liquids examined by us, it presented 
an excellent means of determining whether different velocities of flow in our apparatus 
led to identical values for the viscosity. For if with this substance concordant values 
of 7] were thus obtained, it would be indicated ( 1 ) that, even for the highest velocities 
we have employed, the character of the motion is still linear; and ( 2 ) that the mode 
of correcting for kinetic energy is valid. The observations made in the neighbour¬ 
hood of 30° under the dilferent pressures of 101'22 and 129'94 centims. show that the 
values of t] thus obtained are identical.* 
In reducing the observations of viscosity we have employed for the density at 0 ° 
the value 0'G912, and for the thermal expansion the expression 
V = 1 + -0,^14603^ -f -0099793^ -f -O^SGOlSiS 
(Thorpe and Jones, loc. cit.). 
Taking 
i 7 i = ’002589, 7^3 = ’001944, (calculated) = ’002244 
b = 0°’35 ^3 = 32'’’02 (from curve) = 15°’40, 
we obtain the formula 
_ 3-3891 
~ (144-01 + ’ 
which gives results in very good agreement with the observed values. 
* This fact is even more clearly established in the case of ether—also a very mobile liquid—where 
two independent samples, measured under similar wide variations of pressure, afforded perfectly 
concordant values of 7 (see pp. 519-520). 
