quick overview :

Fortins Barometer :- A glass tube of 6mm bore is contained in an enameled & lacquered brass case, mounted on a polished wooden board with plates for fixing to wall, open plate reflectors & ring & screws for vertical adjustment. The silvered scales, graduated in inches & mm are read by vernier moving by Rack & pinion to 1/200 in & 1/10mm & are enclosed in glass cylinder. A glass cylinder at the lower end of the barometer is provided with an ivory point to which the level of the mercury in the cistern is adjusted before readings are taken. A ring support & three locking screws at base of instrument provide a means of securing the barometer in a vertical positions. Fitted with thermometer with centigrade & Fahrenheit scale. Supplied without mercury but with instruction for filling the barometer.