BETWEEN THE VISCOSITY OF LIQUIDS AND THEIR CHEMICAL NATURE. Gl!? 
Normal Propyl and Allyl Compounds, 
Normal j^ropyl. 
Difference. 
Allyl. 
V- 
Hydrocarbons . .... 
318 
(7) 
304 
Iodides. 
407 
I 
406 
Bromides. 
372 
1 
371 
Chlorides. 
330 
2 
328 
Ethylene and Acetylene Bromides. 
i 
i 
Ethylene. 
Difference. 
Acetylene. 
'/• 
'/• 
Bromides. 
L5.5 
-8 
463 
Here again, is a decided regularity ; the coefficient of the j^i'opyl compound is 
uniformly larger, and the difference tends to increase as the molecular weight decreases, 
the iodides exhibiting the smallest, and the hydrocarbons the largest diflerences. 
In the case of ethylene and acetylene bromides, where the molecular weights are 
higher than in the case of the iodides, the difference for the loss of a double linkage 
and the addition of Hg has become negative. At the boiling-point this difference 
was in no way comparable ’with that of normal propyl and allyl compounds. 
Isologous Hydrocarbons. 
n. 
C„H. 
n* 
0„H2„_2. 
C„H2«_6 
Diff. 
'/• 
Diff. 
Diff. 
'/• 
5 
299 
-12 
311 
4 
295 
6 
318 
14 
304 
-12 
330 
7 
330 
.. 
, . 
,. 
-24 
3.54 
8 
.336 
• 
. . 
-31 
367 
On passing from pentane to amylene the viscosity rises by some 12 units. When, 
however, by the loss of four hydrogen atoms the corresponding paraffin passes into 
isoprene or diallyl the viscosity falls, the fall increasing with the molecular weight. 
Constitution here evidently comes into play. An aromatic hydrocarbon has a 
coefficient which is greater than that of the corresponding paraffin by an amount which 
4 L 2 
