Barometer Siphon Tube

Two glass tubes 220mm long x 8mm bore one closed at the top and other open. Lower ends of two glass tubes are joined by 1 meter of pressure tubing. Both tubes mounted on sliding brackets lockable in any position on metal support rods. Polished wooden stand with graduated scale 0-100 cms, with mms in centre and figured every cm on either side. Supplied without mercury.