Leyden jar condenser set
Date: circa 1908-1909
Inventory Number: 2008-1-0117
Classification: Leyden Jar
Subject:
Maker: Wireless Specialty Apparatus Company (1907 - 1930)
User: Jefferson Physical Laboratory, Harvard University (founded 1884)
User: Cruft Laboratory, Harvard University (founded 1914)
Cultural Region:
Dimensions:
48 x 45.5 x 31.3 cm (18 7/8 x 17 15/16 x 12 5/16 in.)
Description:
A wooden case with ceramic feet that holds six Leyden jars consisting each of a thin glass jar with its lower three-fourths of its surface covered in metal. The jars are arranged in two rows and all are closed on top by a wood frame through which electrodes extend to the inside of each jar. One of the two rows has the electrodes of its three jars connected to knife switches that connect the jars in parallel. The other row has two of the jars connected together with a metal rod, and the third one with its electrode standing alone.
In Collection(s)
Signedon jars' label: WIRELESS SPECIALTY APPARATUS CO. / NEW YORK / DEPOSIT NO 4 / PAT. JULY 21-1908.
Inscribedon tag attached to instruments: Leyden Jar / Condenser Set / c 1908-9 / Made in conjunction / with spark transmitter / for tuning wireless
FunctionLeyden jars were the earliest form of capacitor but were still common until the early twentieth century. They consist of a glass vessel coated on the inside and outside by metal sheet. When these two sheets are connected to different voltages, the jar accumulates electric charge.
This particular array seems to have been assembled at Harvard to demonstrate the effects of different capacitance on the emission or reception of signals.
In radio, a different capacitance leads to a different transmission or reception frequency of a circuit. When connected in parallel, the total charge that the system can accumulate (capacitance) is the sum of that of the connected individual jars. Because of this, this object acts as a capacitor with a variable capacitance depending on which of the jars have their knife switch closed and which ones do not.
This particular array seems to have been assembled at Harvard to demonstrate the effects of different capacitance on the emission or reception of signals.
In radio, a different capacitance leads to a different transmission or reception frequency of a circuit. When connected in parallel, the total charge that the system can accumulate (capacitance) is the sum of that of the connected individual jars. Because of this, this object acts as a capacitor with a variable capacitance depending on which of the jars have their knife switch closed and which ones do not.
Curatorial RemarksCheck object RS0177 for what is likely a similar kind of jar.
ProvenanceFrom the Department of Physics, Cruft Laboratory, Harvard University.