Thanks for reading and for your comments Joe & Paula.
It must have been quite a thing to drive, with so many controls!
The large dial says 'Volts 0 - 1.7 in 0.1V Steps' and states 1 Div = 0.0002 Volts (yes, two ten thousandths of a Volt per Div!). Errm why I wonder?
The other controls are:
Fine Rheostat,
Coarse Rheostat,
Standard Cell Voltage 1.0170 - 1.0890V
Push button makred 'Galv Key'
The pairs of terminals are marked:
'Standard Cell' (For externally connecting a Weston Cell?)
Then: 'G', '1', '2', '3', then '2 Volts'
Rather a pity that it can't talk, and tell us what sort of a life it's had, and what use it was put to? Presumably in a lab, or at the uiniversity? We'll never know.
Presumably they had to use a precision Wheatstone Bridge to measure the many shunts wound from low resistance wire.
I have another Potentiometer made by Cambridge Instruments, which uses an internal Weston Cell (not present), which Colin kindly gave me when we met at the Golborne Swapmeet recently. It brought back fond memories of a 'former life'. During the natural gas conversion era in the late 1960s, for a year I worked in the BG labs designing burners to convert obsolete gas appliances designed for use on coal gas to enable them to work on natural gas. (Had they not been converted, BG would have had to replace the appliances free of charge). We used such an instrument as that which Colin kindly gave me, with a 'black ball thermocouple' suspended in ovens of cookers to check that the oven thermostats were working correctly. The small voltage generated by the thermocouple was balanced with the potentiometer controls against a standard cell and gave an accurrate indication of the oven temperature. I guess that in the forty years that has elapsed since then, that BG thermocouple potentiometer is either in someone's collection, or has long since met its fate as an unloved obsolete relic of a bygone age.
During my apprenticeship with the then 'Gas Board' back in the 1950s gas was still made from coal shovelled into 'retorts' (furnaces), and they used to use 'disappearing filament pyrometers' which was held in front of the burning coal, and adjusted the pyrometer to a point at which the filament was the same degree of redness as the hot coal so the filament 'disappeared', at which point you read off the temperature on the dial. Simple, but clever. If the coal was too hot, they'd reduced the amount of air to it - too cool, increase the air flow. Not just 'stokers' - actually quite a skilled job, as was the work of 'firemen' on the footplates of trains.
At 15, I found it all very scary and was glad when my 3 month stint at the 'gasworks' was over! It was like being in Dante's inferno - flames, noise, heat, smells, hazards everywhere. Mothers used to bring sickly kids into the works to ask if they could breath in the tar fumes to ease their chesty coughs. If it worked at all, I guess the kids stopped coughing out of sheer fear of a return visit! How times change. Back then, the National Health Service was only seven years old - a service that was to be 'free at the point of delivery' (still is), and many if not most people back then, were very reluctant to seek medical help - "I don't hold with Doctors" was a typical comment.
Oh dear, rambling again in 'BOF' mode...sorry about that.
It must have been quite a thing to drive, with so many controls!
The large dial says 'Volts 0 - 1.7 in 0.1V Steps' and states 1 Div = 0.0002 Volts (yes, two ten thousandths of a Volt per Div!). Errm why I wonder?
The other controls are:
Fine Rheostat,
Coarse Rheostat,
Standard Cell Voltage 1.0170 - 1.0890V
Push button makred 'Galv Key'
The pairs of terminals are marked:
'Standard Cell' (For externally connecting a Weston Cell?)
Then: 'G', '1', '2', '3', then '2 Volts'
Rather a pity that it can't talk, and tell us what sort of a life it's had, and what use it was put to? Presumably in a lab, or at the uiniversity? We'll never know.
Presumably they had to use a precision Wheatstone Bridge to measure the many shunts wound from low resistance wire.
I have another Potentiometer made by Cambridge Instruments, which uses an internal Weston Cell (not present), which Colin kindly gave me when we met at the Golborne Swapmeet recently. It brought back fond memories of a 'former life'. During the natural gas conversion era in the late 1960s, for a year I worked in the BG labs designing burners to convert obsolete gas appliances designed for use on coal gas to enable them to work on natural gas. (Had they not been converted, BG would have had to replace the appliances free of charge). We used such an instrument as that which Colin kindly gave me, with a 'black ball thermocouple' suspended in ovens of cookers to check that the oven thermostats were working correctly. The small voltage generated by the thermocouple was balanced with the potentiometer controls against a standard cell and gave an accurrate indication of the oven temperature. I guess that in the forty years that has elapsed since then, that BG thermocouple potentiometer is either in someone's collection, or has long since met its fate as an unloved obsolete relic of a bygone age.
During my apprenticeship with the then 'Gas Board' back in the 1950s gas was still made from coal shovelled into 'retorts' (furnaces), and they used to use 'disappearing filament pyrometers' which was held in front of the burning coal, and adjusted the pyrometer to a point at which the filament was the same degree of redness as the hot coal so the filament 'disappeared', at which point you read off the temperature on the dial. Simple, but clever. If the coal was too hot, they'd reduced the amount of air to it - too cool, increase the air flow. Not just 'stokers' - actually quite a skilled job, as was the work of 'firemen' on the footplates of trains.
At 15, I found it all very scary and was glad when my 3 month stint at the 'gasworks' was over! It was like being in Dante's inferno - flames, noise, heat, smells, hazards everywhere. Mothers used to bring sickly kids into the works to ask if they could breath in the tar fumes to ease their chesty coughs. If it worked at all, I guess the kids stopped coughing out of sheer fear of a return visit! How times change. Back then, the National Health Service was only seven years old - a service that was to be 'free at the point of delivery' (still is), and many if not most people back then, were very reluctant to seek medical help - "I don't hold with Doctors" was a typical comment.
Oh dear, rambling again in 'BOF' mode...sorry about that.
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
