Barometer

“Suppose a to be a long tube, with the piston b so nicely fitted to its inside, as to work air tight. If the lower end of the tube be dipped into water, and the piston drawn up by pulling at the handle c, the water will follow the piston so closely, as to be in contact with its surface, and apparently to be drawn up by the piston, as though the whole was one solid body. If the tube be thirty-five feet long, the water will continue to follow the piston, until it comes to the height of about thirty-three feet, where it will stop, and if the piston be drawn up still farther, the water will not follow it, but will remain stationary, the space from this height between the piston and the water, being left a void space or vacuum.” —Comstock, 1850

Downloads