Gal 5 : Measuring unit of acceleration (increasing speed) due to gravity equal to one centimetre per second in each second. A milligal is 1/1000 of this and occurs (e. g. in measuring differences of gravity in order to find oil
H. J. Porter (Chairman - Technical Committee), Dictionary of Fire Technology, The Institution of Fire Engineers, The Victory Press (Leicester) Ltd. 1979 UK. (Fr Tech - Brit) {81}