536 Scientific Proceedings, Royal Dublin Society. 



glass, cylindrical, closed at each end by ground stoppers, with 

 tubulures attached. The upper tubulure is of fine bore, hardly 1 mm., 

 the lower tubulure of some 3 or 4 mms. bore. The volumenometer 

 is surrounded by a copper jacket, having two large openings cut in 

 its cover for the admission of broken ice or water, and also a tubulure 

 for admitting a thermometer. A fine mark is etched on the lower 

 tubulure at/, and this tubulure is continued by attachment to a 

 smaller vessel c, as shown. This again is connected by a rubber 

 tube connexion with the vessel d, which can be raised or lowered, 

 as will be understood from the plate. The volume of the volumeno- 

 meter is best determined with water. If water is subsequently to 

 be used in it the procedure is as follows : — 



The coupling b is removed and the vessel g inverted in the 

 copper jacket. The wide tubulure is now uppermost, the narrow 

 one below. This is attached to d, and the upper one to an air 

 pump, and distilled air-free water drawn into g, through the 

 lower tubulure till it is quite full. The vessel d is now raised, the 

 connexion with the air pump removed, and when d is so high that 

 water is just swelling out of the tubulure this is closed with a short 

 pinched rubber tube. 



Broken ice is now filled in round the volumenometer and after 

 the lapse of some hours the connection below with d is broken and 

 the fine tubulure closed with a little piece of wax. The upper 

 tubulure is now opened, and the level in the tubulure lowered by 

 applying bibulous paper till it sinks to the mark etched upon the 

 glass. It is then closed with rubber tubing as before. The ice being 

 next removed, g is lifted out, dried carefully, and weighed. This 

 done it is replaced in the copper cylinder, this time in its normal 

 position, and the water let run out. The ice is now returned to 

 the jacket, and after the lapse of some time the volumenometer is 

 closed as before, when the height H of the barometer is read. 

 Another weighing is now made, and by difference the weight of 

 water at 0°C. which has quitted the vessel is calculated, allowing for 

 the weight of saturated air at 0°C. and H contained in the vessel at 

 the second weighing. One or more such operations may be per- 

 formed, and from the known density of water at C C. the volume at 

 the temperature 0°C. calculated. To this must be added, for the 

 complete volume, the volume at ordinary temperatures of the small 

 steel connection with the sphere. It is obvious that the error 



