This fine clock is not from my own collection, the pictures were kindly made available by it's owner (I.F.) with permission to display them on my web site for the enjoyment of others.
The serial number is 1872 with a date of 18/03/1920
Case: Overall dimensions 52.5" x 13.5" x 8". This is very dark in colour and is finished matt black internally. The wood may be beech or pine as these woods were used on these early clocks. They were finished to resemble Rosewood or dark mahogany
Historical note: The history of Gents has been related by D J Bird in great detail (see below) but in brief:
The first Gents transmitter (as they were then called) was made in 1905 and installed in Thornbridge Hall so that pattern of clock came to be called the Thornbridge though Gents labelled them types C1 to C4.
The design was simplified and became known as the Tompion transmitter (C5) this carries the story to 1907.
The design was further simplified and a new patent obtained in 1907. This was regarded as a cheap construction method and enabled Gents to sell more cheaply so production concentrated on the design. By 1909 it was called the Home transmitter and known as C6 if it had no pilot dial or C7 with a dial.
Now to details!
In 1909 the main contacts were only about 1.75 " below the lower pivot. By 1915 the armature and switch lever were an inch longer and there were other detail alterations. The pendulum rod in early clocks was usually of teak moving between two pins on the crutch. The spark quench if fitted, was a single large capacitor across the movement terminals.
After the war several alterations were made one after the other. The main casting was extended at the top so the movement could more firmly fixed by being screwed through holes in the casting to the wall.
Early models of the C7 had "THE B-P PATENT SYSTEM" cast in the main casting and patent dates etc along the lower edge.
By the time they produced serial number 1872 they had changed the lettering on the casting to "PULSYNETIC ELECTRIC SYSTEM" (This change in lettering was not made until around serial 1850) and soon after the casting was extended at lower left side to provide a lower backstop support for the armature.
The clock illustrated fits into the time scale about here.
The next feature to be introduced was a separate pendulum support casting, first offered as an optional feature. This feature is found in number 1977, but is known to be optional as the separate support is not fitted to serial 2043 of 1921
Points to note are:
The single large spark quench capacitor near the top of the case was still being fitted when 1872 was made.
The main casting extended at the bottom left and the longer arms for the main contact.
Invar pendulums came into use quite early and one is fitted to No.1872
The pilot dial looks to be a Mark IIb (two b) which
was only introduced at about the date of No.1872. The catalogue
reference for this was "Fig C9" and it is found with either Roman or
Arabic figures.
All collectors of Gents electric clocks are deeply indebted to D J Bird who has written extensively on the C7 and other Gents clocks. Much of the information in these notes is derived directly or indirectly from that source and is gratefully acknowledged. Collectors are advised to join the electrical horology group of the AHS in order to benefit the detailed information available from the AHS.