98 
DR. T. PJ. THORPE AND MR. J. W. RODGER ON THE RELATIONS 
( 4 .) As regards normal isomeric esters, the formate has the largest and the 
})roplonate the smallest coefficients, and the values of the acetate are larger than of 
the butyrate. 
Comparison of Viscosity Magnitudes at Comparable Temperatures. 
In what follows we deal with the relationships which exist between the various 
viscosity magnitudes—the viscosity-coefficient, the molecular viscosity, and the 
molecular viscosity work—first, at the boiling-point, and, second, at temperatures of 
equal slope, the slope adopted being that employed in our previous paper, viz., 0 ' 0 ^ 323 . 
A. Comparison of Viscosity Magnitudes at the Boiling-point. 
Esters. 
i 
i 
Viscosity-CoefBcients. 
in dvnes per sq. centim. 
X 105. 
Molecular Viscosity. 
?/ in dynes per sq. centim. 
X specific molecular area 
in sq. centims. x 10“^. 
1 
Molecular Viscosity Work. 
)/ in dynes per sq. centim. 
X specific molecular 
vol. in cub. centims. X 10®. 
i 
Methyl. 
Etliyl. 
Propyl. 
Methyl. 
Ethyl. 
Propyl. 
Methyl. 
Ethyl. Propyl. 
Formate . 
312 
289 
278 
492 
555 
620 
195 
243 293 
' Acetate 
266 
253 
246 
508 
567 
626 
222 
268 315 
; Propionate . 
255 
242 
. . 
565 
614 
• « 
266 
309 1 .. 
Butyrate . 
250 
• , 
• • 
630 
• • 
317 
• • • • 
Isobutyrate . 
251 
• * 
• e 
633 
• • 
318 
.. 
Ethers. 
Viscosity-Coefficients. 
// in dynes ^ler sq. centim. 
X 105. 
Molecular Viscosity. 
;; in dynes per sq. centim. 
X specific molecular area 
in sq. centims. X 10^. 
Molecular Viscosity Work.' 
>1 in dynes per sq. centim. ’ 
X specific molecular 
vol. in cub. centim. x 10®. j 
1 
Methyl propyl . 
211 
471 
222 
Ethyl propyl. 
210 
534 
269 
Dipropyl . 
212 
601 
320 ' 
Diethyl 
205 
459 
217 t 
Methyl isobutyl 
210 
534 
269 
Ethyl isobutyl . 
208 
593 
316 1 
As regards the esters, it will be seen that the different series follow the rule obeyed 
in most homologous series, viz., that the viscosity-coefficients diminish as the mole¬ 
cular weight increases. All the differences are negative, and diminish as a sei'ies is 
ascended. 
