Browse Items (54 total)

Prisms have been standard laboratory equipment since Isaac Newton used one in 1666 to study the nature of the spectrum. Most or all of these prisms were made by Duboscq in Paris.

When the large center disk, made of non-conducting material with metallic strips attached, was turned using a hand crank, fixed metallic brushes rubbed against the metallic strips causing them to become charged. The charge was drawn off and collected…

This was the culmination of over a century of development of current-measuring instruments which relied on the interaction of currents with static magnetic fields. These instruments were mounted on a solid wall to prevent vibration, and a telescope…

When this device is connected between two points in a circuit, it measures the relative voltage between the points by passing current through a coil of many turns of fine wire which, in turn, causes the needle to deflect.  

The basic discharger is simply a conductor used to discharge a Leiden jar. The two arms are spread apart at the hinged joint, and the insulated handle prevents the operator from receiving a shock as the knobs are touched against the outer foil and…

The Leyden jar is the earliest form of the condenser or capacitor. The jar allowed the electric charge produced by an electrostatic machine (for instance) to be accumulated and stored for future use. The first jars were made independently in 1745 by…

This is a demonstration device showing two aspects of electric charge. When the conducting sphere atop the vertical stand is charged (e.g. by using a Leyden jar) the horizontal pinwheel device at the top begins to spin as charge is leaked from its…

The Magdeburg hemispheres are a pair of large copper hemispheres with mating rims. When the rims were sealed with grease and the air was pumped out through the valve below the lower hemisphere, the lowered pressure within the sphere made it very…

The telegraph was invented by the artist and scientist Samuel Finley Breese Morse (1791-1872), who conceived the idea of the printing telegraph during an ocean voyage to Europe in 1832. The actuation of an electromagnet in the receiver would cause a…

The tangent galvanometer is a current measuring device. It was first described in an 1837 paper by Claude-Servais-Mathias Pouillet (1790-1868), who later employed this sensitive form of galvanometer to verify Ohm's law. To use the galvanometer, it is…