BETWEEN THE VISCOSITY OF LIQUIDS AND THEIR CHEMICAL NATURE. 461 
Left limb. 
Rig 
lit limb. 
Temp. 
Press. 
Corr. 
n- 
Temp. 
Press. 
Corr. 
n- 
0 
0'20 
103-44 
-000077 
-002527 
0 
0-20 
103-39 
-000077 
•002531 
5-51 
103-50 
-000081 
-002404 
5-42 
103-42 
■000080 
-002409 
10-21 
103-54 
-000083 
-002303 
10-21 
103-46 
-000083 
-002308 
15-82 
103-55 
-000087 
-002193 
15-82 
103-48 
-000087 
-002191 
20-00 
103-55 
-000089 
-002114 
20-05 
103-48 
-000089 
-002115 
25-71 
103-69 
-000092 
-002015 
25-79 
103-62 
-000092 
-00-2017 
30-68 
103-69 
-000095 
-001930 
30-71 
103-60 
-000095 
-001932 
32-57 
103-72 
-000096 
-001904 
32-62 
103-63 
-000096 
-001901 
In reducing the observations we have employed Perkin’s value f/(15°/15°) = 0‘G7037 
for the relative density, and the expression 
V = 1 + -03145871^ + -05338435^2 + -03339536^3 
for the thermal expansion (Thorpe and Jones, loc. cit.). 
Taking 
7}^ = -002529 
= -001903 
7)2 (calculated) = -002194 
= 0°-20 
ig = 32°-59 
t .2 (from curve) = 15‘^-75, 
we obtain 
28-910 
~ (187-24 + t) 
1-7855 ’ 
which almost exactly reproduces the observed values :—■ 
Mean temp. 
> 1 - 
Difference. 
Observed (mean). 
Calcnlated. 
0 
0-20 
-002529 
■002529 
■000000 
5-46 
-002406 
■002407 
+-000001 
10-21 
-002306 
■002305 
-•000001 
15-82 
-002192 
■002192 
•000000 
20-03 
■002114 
■002113 
-•000001 
25-75 
■002015 
■002013 
-•000002 
30-69 
■001931 
■001932 
+-000001 
32-59 
■001903 
■001903 
•000000 
Isoprene (Pentine). C 5 Hg. 
We are indebted to Dr. Tilden for a liberal supply of this hydrocarbon. It was 
obtained from turpentine. On distillation the greater part boiled between 35°-5 and 
37°-0. 
A determination of vapour density gave ; 
Found, 35-73 ; Calculated, 34-00. 
