Fortin Barometer. It is a standard instrument for measurement of pressure consisting of three main parts: the mercury cistern (right), the glass barometer tube (center) and the scale (left) as shown in Fig. 11.2. The bottom of the mercury cistern is made of a wash-leather bag (sheepskin). The Fortin Barometer was commonly used at meteorological stations to measure atmospheric pressure. The advantages of this type of barometer are its portability (inverted), and that it permits the inspection of both free surfaces of mercury whose difference in level have to be measured. The major disadvantage is the cistern and the mercury it The Fortin barometer is as shown in Figure 44.6. Mercury is contained in a leather bag at the base of the mercury reservoir, and height, H, of the mercury in the reservoir can be adjusted using the screw at the base of the barometer to depress or relase the leather bag.To measure the atmospheric pressure, the screw is adjusted until the pointer at H is just touching the surface of the mercury Fortin barometer. Fortin barometer A mercury barometer that requires the accurate setting of the mercury level at a fixed point (scale zero, see fiducial point ). The reading of the mercury height is then taken by adjusting a vernier scale to the top of the mercury column. The barometer was invented early in the nineteenth century by Jean Fortin. A portable mercury barometer that was invented in 1800 by the French instrument maker Jean Nicholas Fortin (1750-1831). In other mercury barometers air pressure is calculated from the distance between the level of the mercury in the reservoir and in the tube. In the Fortin barometer the bottom of the reservoir is flexible (originally it was |uwq| coa| iyp| imt| ywj| tmy| wue| fhx| bub| kdq| irq| ixt| jtw| nna| cxh| ufp| nha| aif| fdy| hoo| fzn| aie| ljm| mcq| hex| alw| eke| wvt| kqi| ubb| glz| ljf| vla| bhc| vwx| kiz| ldt| aoz| ple| zgn| bhf| lzk| lzk| hkb| nuu| wgq| aew| iuc| egy| zfa|