colored engraving of an electrical experiment
Date: after 1780
Inventory Number: 1998-1-1105
Classification: Print
Subject:
Associate Name: Clemens Kohl (Austrian, 1754 - 1807)
Artist: Johann Sollerer (1747 - 1809)
Cultural Region:
Place of Origin:
Dimensions:
35.8 x 28.1 x 0.1 cm (14 1/8 x 11 1/16 x 1/16 in.)
Material:
DescriptionMatted hand-colored print of two men performing an experiment with a plate electrical machine. The machine is an English-type electrical machine, similar to DW0504. The machine consists of a glass wheel mounted in a wooden frame. The sides of the frame are bearings for the wheel axle, which is being turned by a crank. At the top of the frame is a pair of rectangles rubbing against the glass.
The prime conductor is silver in this print. It is mounted on a single column. The rod forks out into two collectors positioned near the two sides of the disc. Next to the end of the collecting rod is cylinder with a conical top and a ball at the top of that.
The man on the right is in blue, the one on the left is in red. Both are wearing powdered wigs and culottes. The man on the left is turning the wheel of the electrical machine while touching a rod to the man on the left's hand. The rod is attached to what is most likely a chain that extends down to the floor. The man in red is standing on a table and touching a rod to the prime conductor.
The prime conductor is silver in this print. It is mounted on a single column. The rod forks out into two collectors positioned near the two sides of the disc. Next to the end of the collecting rod is cylinder with a conical top and a ball at the top of that.
The man on the right is in blue, the one on the left is in red. Both are wearing powdered wigs and culottes. The man on the left is turning the wheel of the electrical machine while touching a rod to the man on the left's hand. The rod is attached to what is most likely a chain that extends down to the floor. The man in red is standing on a table and touching a rod to the prime conductor.
Signedbelow print: Sollerer del.[drew (delineavit)] Cl. Kohl direxit. [supervised.]
Inscribedabove print: No. 41.
below print on mat: Science / Electric Spark
below print on mat: Science / Electric Spark
FunctionContact between two different substances facilitates a transfer of electrostatic charge. Because the surfaces are usually rough, there is less contact, and therefore less charge transfer, than if the surfaces were completely smooth. Rubbing the two substances together facilitates a greater buildup of charge. Nonconductors are better at holding the charge.
The glass disk is turned with the crank and rubs against the felt pieces at the top and the bottom of the bearing. The charge builds up on the glass. The collecting rod collects the charge, and the two arms conduct the charge to the cylinder at the end.
The two men are most likely discharging the machine by connecting the prime conductor to ground. The circuit would be completed when the man in red touches the prime conductor and the man in blue touches the man in red with his rod. The man in red is standing on a table so that he, himself, is not grounded.
The glass disk is turned with the crank and rubs against the felt pieces at the top and the bottom of the bearing. The charge builds up on the glass. The collecting rod collects the charge, and the two arms conduct the charge to the cylinder at the end.
The two men are most likely discharging the machine by connecting the prime conductor to ground. The circuit would be completed when the man in red touches the prime conductor and the man in blue touches the man in red with his rod. The man in red is standing on a table so that he, himself, is not grounded.
Curatorial RemarksKohl and Sollerer need to be added to the database. Also, I'm not quite sure how to attribute Kohl here, because "direxit" means he supervised the work.