IN THE HALL OF THE ROYAL SOCIETY. 
543 
in a proper position over a small fire-place, with a temporary flue (t, n) at the 
foot of the well-staircase conducting to the apartments of the Society. With 
considerable difficulty and contrivance, the case with the glass tubes was in- 
troduced, by permission of the Antiquarian Society, through their library, and 
fixed against the stairs in a perpendicular direction, immediately over the 
stuffing-box ; and the front of the box being removed, the tube was unpacked 
and suspended from above over the aperture. It was then very carefully 
lowered into its proper position in the boiler, and the wooden stays being 
screwed into their places, it was firmly adjusted. The stuffing-box (m, n ), 
through which it passed into the boiler, was then packed with tow, and in- 
tended to be perfectly steam-tight. Part of the upper end of the deal-case 
was removed with a saw, so as to leave about six feet of the glass tubes 
exposed. 
The object of the whole arrangement was as follows : first to boil the water 
in the cistern thoroughly, suffering the steam to escape by the cock ( s ), and 
then, by closing the latter, to raise the water in the tube, by the elastic force 
of the vapour acting upon its surface, till it issued in a jet from the small stop- 
cock upon its summit. When a sufficient current had thus been forced up, 
to secure the thorough wetting of the tube, and the total extrication of all 
particles of air, it was intended to close the stop-cock at the top while the 
water was still flowing, and at the same moment to relieve the pressure below 
by opening the cock upon the boiler, and again suffering the steam to escape. 
It was conceived that when the whole apparatus was cool, the column of water 
would subside, till it afforded a balance to the pressure of the atmosphere ; 
when the small tube might be sealed by a dextrous application of the blow- 
pipe, and the stop-cock removed. 
Everything being ready for the experiment, a preliminary trial was made 
of the apparatus on the 10th of June. The boiler was carefully washed with 
boiling distilled water, and the cover being screwed down, it was filled with 
distilled water to within five inches and a half of the top. The fire was then 
lighted in the grate, and in about two hours and a half a powerful current of 
pure steam issued from the cock ( s ). When this had continued for about 
half an hour, the cock was gradually closed, and the water rose very slowly in 
the tube. During its rise it oscillated backwards and forwards two or three 
4 a 2 
