BETWEEN THE VISCOSITY OF LIQUIDS AND THEIR CHEMICAL NATURE. 551 
Fig. 6. 
The position of the curve for diallyl is interesting, for when one alljl group only 
occurs in the molecule, as in the case of the allyl halides {v. infra), the curve for the 
allyl compound lies between the curves for the corresponding normal and isopropyl 
compounds, and is thus to the left of that for the normal compound only. When, 
however, two allyl groups occur in the molecule, as in the case of diallyl, the curve 
obtained lies to the left of that of the isopropyl (isohexane) as well as that of the 
normal propyl compound (hexane). 
Iodides. 
The iodides investigated were methyl iodide, ethyl iodide, isopropyl iodide, propyl 
iodide, isobutyl iodide, and ally] iodide. Fig. 7 represents the results obtained. 
Here striking regularity is again obvious. The curves are all ot the same general 
