acidometer

A hydrometer, especially one that is used to measure the strength of an acid.

If the liquid becomes denser, i.e., of greater specific gravity, the acidometer rises, so that more of the tube and its scale is exposed above the liquid, and vice versa.

If it shows by the reading of the acidometer, which is left to float in the electrolyte, that its specific gravity has increased from 1,150°, its density when first poured in, to 1,210 or 1,220 toward the end of the estimated number of hours of charging, then it may be taken for granted that charging has been continued as long as necessary.

Any of various other devices used to measure acidity, either chemical or electronic.

We think the acidometer a very dangerous instrument in the hands of the inexperienced, as the solution of ammonia is subject to the influence of air so much.

Acidometer tests (electronically measuring decay acids on the teeth) made 30 minutes after brushing with ordinary tooth paste, showed “dangerous decay acids”, in most every case.