Labels:text | sketch | drawing | diagram OCR: 7. P I B A, a tripod, with levelling screws; BB, a vertical pillar, to which is attached, C, a mercurial trough, movable by a rack and pinien, aa ; DD, a glass cylinder, 36 inches long, with an internal diameter of 4 inches, containing three tubes, F, G, H, which communicate with one F another and with the exit- pipe, h, by the apparatus Ef E. The rest of the 6 figure will be sufficiently 12 intelligible from the des- cription given in the text. 8 ECSOL A