Early Electric Seismometer
4th qtr, 19th Century
This is a very early and
unusual electric seismometer, produced by the famous Italian
company Jest, sometime between 1850 and 1880.
The device consists of a heavy brass sphere suspended by a wire, with a
needed attached to the bottom of the sphere. The needle is
centered in an adjustable contact mounted in the wooden base. In
the presence of an earthquake the sphere would move, causing the needle
to touch the contact, and thus closing a circuit to ring a bell.
The apparatus in enclosed in a glass bell which prevents false alarms
from the movement of air.
This is probably one of the earliest electric seismometers and is an
excellent example of the use of electricity in a broad range of
applications that took place during the last half of the 19th century.
Lippman Caplillary Galvanoscope
1st quarter, 20th century
Used for measuring electric charge. A small drop of mercury in the
horizontal capillary tube moves under the influence of an electric field
applied to the two electrodes. The amount of charge is indicated by the
distance the drop moves.
Volta Hydrogen Lamp
2nd Qtr, 19th Century
The hydrogen lamp was invented by Alessando Volta (1745-1827) in
Volta lamps were very popular demonstration devices due to the
explosion and bright flame when the lamp was ignited.
Two identical pieces, each
made of hand-blown glass cups 8-1/2" high mounted with wax on 6-1/2"
mahogany base with elaborate binding posts on either side of cup.
Pictured and described as a "Decomposing Cell" in Davis' Manual of
Magnetism pg. 42, fig 28 (1848) and Pike's Catalog (1848) Vol. I pg.
340, fig. 402.