1910-11.] Dynamic Method for measuring Vapour Pressures. 179 
VIII. — A Dynamic Method for measuring Vapour Pressures, with 
its Application to Benzene and Ammonium Chloride. By 
Alexander Smith and Alan W. C. Menzies. 
(MS. received July 25, 1910. Eead November 7, 1910.) 
The simple “ submerged bulblet ” apparatus for determining vapour 
pressures, previously described in these Proceedings (vol. xxx. p. 437), 
may be modified to assume the form shown in fig. f. The substance, 
solid or liquid, is placed in the bulb A of this dynamic isoteniscope. 
The advantages gained are, that the new apparatus may be used for 
high pressures, that the confining fluid (bulb B) is reduced in amount, 
and that the thermometer is inserted directly in the bath and its bulb 
