John Frederick Simmance
1931 Obituary 
JOHN FREDERICK SIMMANCE devoted his unusual inventive abilities to the development of recording instruments suitable for the control of gasworks operations and for power users. When he first turned his attention to this specialized branch of engineering it was a comparatively new field, and he was subsequently responsible for many new instruments.
Born in 1859, he was trained in the works of Messrs. Sugg and Company, becoming manager of their North of England works in 1886.
In 1891 he commenced practice as a consulting mechanical and ventilating engineer. Following the invention of his eduction valve system of ventilation, gas governors, water-heaters, and automatic gas-meters, he became managing director of the firm of Messrs. Simmance and Abady, gas-meter makers.
He also filled a similar position for Messrs. Alexander Wright and Company at a time when this old-established firm, which had attained considerable eminence as the producers of the first slot meters for gas supply, had fallen on evil times. He soon restored its fortunes and brought it to a higher degree of efficiency than it had hitherto enjoyed.
Mr. Simmance was responsible for the development of the flicker photometer head, whereby lights of differing colours could be accurately compared for their illuminating value, and he invented the gravitometer, a delicate instrument for continuously recording the specific gravity of a stream of gas. His standard water-flow gas calorimeter has been widely used in gas works for the past twenty-five years, and he also invented three different forms of recording gas calorimeters. In addition he devised a series of selective automatic recording gas analysers of simple and robust construction, the operation of which is effected merely by the flow of a very small stream of water.
He had been a Member of the Institution since 1899, and his death occurred on 4th February 1931.
He was also a Member of the Institution of Civil Engineers.