Wheel Barometer

| View Cart ⇗ | Info

“The whole length of the tube of the wheel barometer, from C to A, is 34 or 35 inches, and it is filled with mercury, as usual. The mercury rises in the short leg to the point a, where there is a small piece of glass floating on its surface, to which there is attached a silk string, passing over the pulley p. To the axis of the pulley is fixed an index, or hand, and behind this is a graduated circle, as seen in the figure. It is obvious, that a very slight variation in the height of the mercury at o, will be indicated by a considerable motion of the index, and thus changes in the weight of the atmosphere, hardly perceptible by the common barometer, will become quite apparent by this.” —Comstock, 1850


J. L. Comstock A System of Natural Philosophy: Principles of Mechanics (: Pratt, Woodford, and Company, 1850) 154


TIFF (full resolution)

711×2400, 262.9 KiB

Large GIF

303×1024, 38.4 KiB

Medium GIF

189×640, 20.8 KiB

Small GIF

94×320, 7.7 KiB