As was mentioned in our earlier Moto Meter post, a follow up would be coming to show you the very interesting Calometer, along with the prolific designs of Harrison H. Boyce, who developed the Boyce Moto Meter. He invented many other interesting devices, but seemed to concentrate on temperature recording devices for vehicles.
Mr. T. H. Whiting of Edgbaston, England, who worked at the Wilmot Manufacturing Co. Ltd. of Birmingham, England, invented the unusual temperature gauge seen (above). The principle the Calometer operates on, was based on two strips of dissimilar metals (bi- metal), mounted lengthwise in a vertical tube and attached at one end to a toothed quadrant. When the temperature rises, the two strips of metal expand differently and straighten, with the result that the quadrant moves and the pointer turns. The Calometer (introduced in 1925), was a fairly common and accurate temperature gauge in the UK by the late 1920s.
The photo (left above) shows how the Calometer looks from the cockpit of a Model T Ford. The period illustration in the (center above) is an ad by Wilmont. The (right hand) patent drawing, shows a very similar design by Boyce, who filed for a patent on his design on May 27, 1927. If you study his drawing, it will give you a very clear view of how these types of bi – metal devices work. Color photos courtesy of Chris Bamford.
One difficulty with any of these devices is they are quite hard to read at night and that led to the lighted Moto Meter coming on the scene next. The design above by Boyce, was very interesting, but how well it actually worked in practice is unknown. He mounted a tube filled with neon gas inside of the body of the unit and used the high voltage current from a spark plug lead to ignite the neon gas.
Three more Boyce designs are see here, (above left) is another spring controlled unit with a dial and pointer. In the (center above) is a device for measuring the temperature of the water, instead of the air temperature above it, as the liquid type of Moto Meter does. On the (right above) is a device for telling the motorist the level of the water in the radiator.
Boyce also later on designed an add on device for illuminating the standard type of meter (left above), but this time mounted the device on the outside on the unit. He also developed and patented other standard types of temperature gauges and in the (center above), can be seen one for an air – cooled engine, which is dipicted on Franklin. And finally perhaps he could see the end of the Moto Meter was coming (right above), when he designed this “Instrument Board Mounting” and applied for a patent in 1927, which he received in 1930.