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A vertical surface on which information can be displayed to public view

"AB is a wheel with a broad rim, or felly. A wine glass partly filled with water is placed on the inner surface of the felly, and the wheel is then made to revolve rapidly round the axle O. If the proper amount of motion be communicated to the wheel, not only will the wine glass keep its place on the felly, but the water also will remain in it..." —Quackenbos 1859

Centrifugal Force Demonstration

"AB is a wheel with a broad rim, or felly. A wine glass partly filled with water is placed on the inner…

"On the top of a short pillar is placed a card, and on the card a brass bal. Beside the pillar is fixed a steel spring, with an apparatus for drawing it back. If the spring is drawn back and the suddenly released, it will drive the card from the top of the pillar, while the ball in consequence of its inertia will retain its place." —Quackenbos 1859

Inertia Demonstration

"On the top of a short pillar is placed a card, and on the card a brass bal. Beside the pillar is fixed…

"... balance a card with a penny placed upon it on the tip of one of the fingers of the left hand, and strike it suddenly with the middle finger of the right hand, as represented [here]." —Quackenbos 1859

Inertia Demonstration

"... balance a card with a penny placed upon it on the tip of one of the fingers of the left hand, and…

"While his horse is going at full speed, he jumps over a rope extended across the ring, and regains his footing on the saddle without difficultly. To do this, he has only to leap straight up as he comes to the rope, for his inertia bears him along in the same direction as the horse." —Quackenbos 1859

Inertia Demonstration

"While his horse is going at full speed, he jumps over a rope extended across the ring, and regains…

"... a thin stick resting on two wine glasses may be broken by a quick blow with a poker in its centre (sic), without injury to its brittle supports." —Quackenbos 1859

Inertia Demonstration

"... a thin stick resting on two wine glasses may be broken by a quick blow with a poker in its centre…

"Let the are of the piston a be 20 square inches; of b, 7 sq. in.; of c, 1 sq. in.; of d, 6 sq. in.; of e, 8 sq. in; and of f, 4 sq. in. If... a force of five pounds be applied at c, a pressure of five pounds per square inch will be transmitted in all directions, and in order that there shall be no movement, the required pressure must be applied by all the other pistons in proportion." —Hallock 1905

Water Pressure Demonstration

"Let the are of the piston a be 20 square inches; of b, 7 sq. in.; of c, 1 sq. in.; of d, 6 sq. in.;…