between the viscosity of liquids ynd their chemical nature, 427 
Thread towards end . .. 1*5602 centims. 
Thread at zone of sealing. 1*5573 „ 
Thread towards the end . 1*5581 ,, 
It is evident that no appreciable modification in the dimensions of the bore had 
been brought about in making the glischrometer. The measurements indicate also 
the increase in the section of the tube towards the end B.^, which was apparent from 
the previous optical measurements. 
Length of the Bore of the Capillary Tube. —From the fact that the ends of the 
tube were somewhat oblique, it was a matter of some difficulty to find the exact 
length of the bore. When tlie glischrometer was laid flat on the table with that side 
undermost upon which the various marks m^, &c., were etched, owing to the 
obliquity of the ends the termination of the bore could not be seen, and even with the 
etched side uppermost the termination was not quite definite. Accurate readings 
were obtained, however, by introducing a thread of mercury into the tube, the 
quautity of mercury being so arranged that at either end the thread expanded into a 
spherical globule. With the etched side uppermost the points where the bore ended 
and this expansion took place could be clearly made out. Measurements were then 
made with a Brown’s calibrating instrument of the length of the bore indicated in 
this way, when the bore was parallel to the line of motion of the reading microscope 
and when different parts of the scale of the instrument were used. 
From twelve measurements the mean observed length at I5°*95 was 
4*9318 centims. 
Corrected for the expansion of the brass scale and the expansion of glass, at 0° 
this value became 
4*9326 centims. 
Mean Radius of the Bore of the Tube .—The mean radius was determined by 
weighing a globule of mercury which occupied a known length of the bore of the 
tube. After several trials the method adopted was as follows :—The glischrometer, 
perfectly clean and dry, was fixed with the capillary tube vertical, the left limb being 
uppermost, and, of course, horizontal. Into this limb was next introduced a long 
piece of drawn-out glass tubing containing a small globule of pure re-distilled mercury. 
One end of this piece of tubing was placed on the flat end of the capillary, and to tlie 
other end was attached a j^iece of rubber tubing. By gently compressing the rubber 
tubing the globule was transferred to the flat end of the capillary. The drawn-out 
tube was then removed, and a small india-rubber ball, which could be used as a 
compressing syringe, was attached to the free end of the left limb. By gently tapping 
the glischrometer the globule was brought over the bore of the capillary, and, when in 
this position, by compressing the ball it was slowly driven into the tube. After a 
3 I 2 
