Butler and Sheridan — Account of a Netv Oedanometer . 477 



bore and 50 cms. long. The upper end of the cylinder is closed by a second 

 reducing coupling, which slips over like a cap instead of being screwed on. 

 (At first we used a screw-on cover, but experienced considerable difficulty in 

 removing it at the end of the experiment owing to the great pressure.) The 

 cover is held in position by six five-sixteenth bolts D, screwed into the cylinder. 

 Wlien the cover is attached, any space that remains free is filled up with sand 

 poured in through the neck. 



A screw-in adapter (not shown in the figure) is then inserted, and serves 

 to keep the sand in place. The water is now turned on from below, and in 

 the course of a minute or so appears at the neck. The results given by this 

 apparatus are shown in the accompanying Table II. 



Maximum pressure 26-9 atmospheres. 



The principal difficulty in using this apparatus was to secure the 

 manometer tube firmly to the rubber bag. 



The end of tlie tube may be drawn out, forming a neck which helps to 

 hold tlie wire. Even with this arrangement the tube tends to shoot out 



SCIENT. PEOC. R.D.S., VOL. XIV., NO. XSXV. 4 F 



