dasymeter

noun

1. (dated)An instrument for testing the density of gases, consisting of a thin glass globe, which is weighed in the gas or gases, and then in an atmosphere of known density.

   “The dasymeter consists of a two-armed lever or balance beam, on one arm of which is a hermetically sealed glass sphere of 3 litres capacity, while the other arm carries a balancing weight. The higher the percentage of carbonic anhydride contained in the gas to be examined, the higher will be its specific gravity, and consequently the greater its weight.”

   “With the idea that regulation of air supply would secure great economy of fuel, an instrument called a “dasymeter” has been invented to indicate the percentage of carbonic acid in the products of combustion; the weight of a vessel, through which gases are being continually drawn from the chimney of a boiler, is indicated on a scale which shows the percentage of carbonic acid compared with the weight of pure air.”

   “Spring-balances are in use in numerous early forms of so-called dynamometers, dasymeters, etc., in machines used for testing paper, textile fabrics, wire, etc., as in the apparatus of Hartig-Reusch, Wendler, Martens.”