Davis Derby Instruments
Davis Derby produced various types of Clinometers and angle finders as early as 1860.
There is evidence that the Abney level similar to this type appeared in a 1902 catalogue.
Figure 1 Abneyís Level
Derby produced air powered lamps from the 1920ís up to 1988. Versions of this
lamp were approved for use in gassy atmospheres and consequently found
applications in mines, quarries, sewer work and for tank cleaning operations.
Figure 2 Compressed Air Lamp
John Davis announced in the Derby Mercury on February 12th 1845 that Biramís patent anemometer would be ready in a few weeks. Davis Derby produced anemometers based on the Biram patented design from 1845 up to 1960.
Various designs were manufactured including pocket versions and self-timing anemometers.
Anemometers were featured in the companyís catalogue up to the 1950ís, the anemometer business was sold to Negretti and Zambra in the 1950ís
Figure 3 1850 Biramís Anemometer
Figure 4 4īī Anemometer and case
Figure 5 Anemometer
The Dumpy level was used in surveying operations above and below ground. It can be used for some of the applications of the theodolite.
The Dumpy level was in production in 1890ís often used on railways, tunnelling and irrigation work.
In 1850 John Hedley, one of H.M. Inspectors of Mines, being convinced of the inconvenience of miners' compasses and dials then in vogue, collaborated with John Davis (the founder of the firm), and the Hedley Dial was evolved John Davis included a Hedley dial in his 1860 price list. The price was £7:10:00.
Figure 7 Hedley Dial (1930)
The company introduced many improvements over the years and continued to produce Hedley dials up to the 1950ís
The Hedley dial is designed for levelling and direction
Figure 8 Hedley Dial (1930)
John Davis was fascinated by surveying instruments and these were included in the 1860 price list, but were known to be in production prior to that date. The theodolite was used for surveying and levelling operations in mines and quarries.
This particular model was manufactured in 1866, theodolites
were manufactured up to the late 1950ís
Figure 10 Theodolite 1866
Davis Derby produced various types of wet and dry thermometers, (Hygrometers). These devices were in manufacture from the mid nineteenth century. They were listed in the 1860 price list and were included in catalogues in the 20th century. The version shown here is a hand held device which is designed to swung like a football rattle.
Figure 11 Edney Swing Hygrometer
Little is known about the Hydrogen tester, but it was used for testing air balloons
Figure 12 Hydrogen Tester
Electric lamps were produced from around 1920 and were still in production
Figure 13 Davis Electric Lamp
Figure 14 Davis Derby Hand Lamp
Figure 15 Little Demon Exploder
Figure 15 Evershedís Portable Ohmmeter
During World War 2, Davis Derby undertook essential war work and produced various instruments including altimeters for Wellington bombers.
Figure 16 Altimeter for the Wellington Bomber
The Kirkby 2A Haydock lamp was
in production in 1940 (and probably for many years before that). The lamp which
was described as being ďof large candle-power and convenient in size and
Figure 17 Davis Kirkby 2A Haydock Lamp
Figure 18 Davis Kirkby Lamp