G48 
MESSRS. T. E. THORPE AND J. W. RODGER ON THE RELATIONS 
Observed. 
Calculated. 
1 
Difference ! 
per cent. 
Amylene. 
665 
627 
5'7 
Methylene clichloricle .... 
600 
632 
- 5-3 
Chloroform. 
747 
843 
- 12-8 
Carbon tetrachloride .... 
854 
1055 
- 23-5 
Carbon dichloride. 
1032 
1134 
- 9-9 
Ethylidene chloride .... 
702 
728 
- 3-7 
Carbon bisulphide. 
618 
.521 
157 
Methyl alcohol. 
358 
375 
- 47 
Water. 
206 
255 
- 23-8 
The calculated value for amylene is obtained by assuming that an iso grouping and 
a double linkage occur in the molecule. If no iso group be assumed to exist, the 
calculated value is 648, which is considerably nearer that found. According to 
Dr. Perkin, however, the sample is (B isoamylene. 
The values for the chlormethanes are calculated from the values of carbon and 
hydrogen, and the value of chlorine in monochlorides. The comparison is given in 
order to show tliat as chlorine accumulates in the molecule the observed values 
differ more and more from those calculated in this manner. In a similar way the 
value for carbon dichloride, calculated on the assumption that a double linkage occurs 
in the molecule, is also far in excess of the observed value. The observed value for 
ethylidene chloride is compared with that calculated for ethylene chloride; the 
difference is due to the difference in the constitution of the two isomers. 
In calculating the value for carbon bisulphide, the value possessed by singly-linked 
sulphur in the alkyl sulphides has been used. The difference is, no doubt, due to the 
altered condition of sulphur in the bisulphide. 
The values of methyl alcohol and water are ’calculated by means of the value of 
hydroxyl oxygen as deduced from the acids. It is evident, especially in the case of 
water, that the observed numbers differ wddely from those calculated in this way. 
As similar relationships are given by these substances when the values of the 
molecular viscosity work are compared, their behaviour will be discussed more fully 
at a later stage. 
Molecular Viscosity at Slope ‘04987. 
[t) in dynes per sq. centim. X siieeific molecular area in sq. centims. X lOh) 
On finding the ratios of the molecular viscosities at the two slopes '0^987 and 
•O 4323 , a practically constant number was obtained as in the case of the viscosity 
coefficients. Its mean value was 1‘928, the average difference being ‘032 or 1‘66 per 
