701 702
702 INTERRUPTER: SELF-ACTING (590) before 1882
Table 180 x 130 x 125
The electromagnet pulls down a bar at the end of a balance arm the
opposite end of which has a heavy cylinder. The contact is broken, the
electromagnet ceases to act, and the weight falls, repeating the cycle. A
form ofWagner ‘hammer’. Guillemin (1891), 393.
703 INDUCTION COIL (685) 1897
Unsigned; French manufacture
Base 340 x 160; length of coil 160; diameter of centre coil ^
Ruhmkorff-type induction coil used with wireless transmitter 785. Base
of mahogany holding condenser underneath; coil, held between walnut
discs, is of thin iron wire. Wagner-type hammer interrupter. Stamped
on one disc is a monogram: CM Breveté S.G.D.G. Purchased from H.
Meeuwig for Dfl. 129 in November 1897.
704 INDUCTION COIL (686) 1865
Signed: Siemens & Halske Berlin No. 773
Base 380 x 130; overall height 325; coil diameter 86
Ebonite casing and supports to coil, which has a walnut base. Iron rod
core; Wagner hammer interrupter. Brass contacts labelled C, A, E, O
Coil support stamped: 3206E / 19024U / U 195 / EO, 2. Above are
two conductors, adjustable horizontal rods with locking screws; one
ends in a point, the other in a disc (diameter 80). The invoice from the
maker is dated December 1865 and is for 85 Thaler. Payment of Dfl
171.85 included transport, and probably the contact breaker below,
705.
Siemens & Halske was founded in 1847, and became specialists
in electrical equipment.
705 CONTACT BREAKER (687) 1865
Unsigned; probably Siemens &. Halske, Berlin
Baseboard 280 x 172; overall height 3/72
Mahogany board with black lacquered wooden pillar supporting brass
housing for clockwork mechanism with iron winding key. At top left of
housing is brake lever, which releases the clockwork to drive a four-bladed
pawl, acting on a lever bar and causing the contact to oscillate in a
vertical direction. Maximum 4 vibrations per second, minimum 2.
Speed adjusted by air brake at top; also adjustment for travel of lever.
Two contacts, one in iron cylinder cup at top of brass pillar; the other
in a glass cylinder with ebonite lid. Cylinder is mounted in brass collar
on arm that can be adjusted for height. Brass bar contacts; two keys
with ivory grips. For purchase, see 704.
706 INDUCTION COIL (1181) 1/4 20th C.
Signed: Allgemeine Elektricitäts-Gesellschaft Berlin [N°] 183
Base 710 x 300 x 126 high; overall length 1,070; coil diameter
200, length 590
A Ruhmkorff induction coil with ebonite insulation. On the top are
contacts from the ends of the secondary coil, with a disc at one end and
a long rod in the other, which moves in a sleeve to adjust the spark-gap.
The Annual Report. 1920-21 records purchase for Dfl. 150, probably
second-hand. For references, see 696. Ernecke [1905], 297, fig. 8753.
707 ELECTRO-MEDICAL INDUCTION COIL (698) 1843
Signed: WATKINS & HILL 5 CHARING CROSS
LONDON
Base 151x152; overall height 260