Beckman’s first pH meter – predecessor of Model G. This is a picture of original model made in 1934 and patented. Picture courtesy of Beckman Coulter, Inc.
Idea soon prooved to be working and in 1936 Beckman decided to try to sell the pH meter commercially as Model G acidimeter, later renamed to Model G pH meter. He decided to put whole apparatus – amplifier, electrochemical cell, electrode, calibration dials, batteries and measuring gauge – into one wooden box, idea not so obvious in 1936 as it is now. Initially market was evaluated as 600 pH meters that will saturate global demand in 10 years. First year sales reached 444 items, showing that new market for measuring devices was discovered. Model G was made and sold till fifties, with device serial numbers reaching 126 thousand range in 1955.
Model G pH meter. Device was closed in wooden box 12″ wide by 8″ deep by 9″ high. It had a leather carrying handle, but – as for todays standards – was hardly portable, weighting almost 8 kilograms. Reference electrode and glass electrode were fastened to the door and could be used for measurements in this position, but they could be also removed if necessary). Picture courtesy of Beckman Coulter, Inc.