Experimental researches on the movement of atmospheric air in tubes / by W.D. Chowne ; communicated by John Bishop.

  • Chowne, William Dingle, 1791-1870.
Date:
[1855]
Catalogue details

Licence: Public Domain Mark

Credit: Experimental researches on the movement of atmospheric air in tubes / by W.D. Chowne ; communicated by John Bishop. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    4/14 (page 4)
    escent, it was found that when the slide valve closed the lower orifice of the tube, the disc of tissue paper remained perfectly quiescent; but that when the slide valve was withdrawn, leaving the lower orifice open, oscillations of the paper occurred, and it was projected at a small angle towards the upper orifice of the tube, demonstrating the existence of a feeble current of air through the apparatus. Fig. 5. Fig. 6. ' V. Slide valve. D. A disc which occupies nearly the whole area of the tube. The preceding experiment having proved the existence of a cur- rent of air within the tube, of sufficient force to move a light body, the author next proceeded to ascertain the velocity of the current by means of an anemometer, in the form of a horizontal fly-disc, D, suspended within the lower oriflce of a tube (fig. 6), bent twice at right angles below. The revolving disc was made of a circular piece of stout writing-paper, cut into twenty-four equal segments, from the circumference to near the centre, each of the segments being after- wards inclined at an angle of twenty-five degrees*, like the vanes of a windmill; so that when properly suspended, a current of air entering the lower orifice of the tube would cause the disc to revolve from right to left. The disc was suspended in the same manner as the needle of the mariner’s compass, and by the same means. * A nearer approach to an angle of 45 would have crippled the paper, sO that it would not have preserved the horizontal position.