Dovolj točno in hitro je gostoto mogoče določiti s plavajočimi hidrometri, ki omogočajo sklepanje o gostoti tekočine glede na globino potopitve z odčitavanjem z graduirane lestvice.
Sufficiently accurate and quick determinations of density may be obtained by the floating hydrometers, which allow the density of a liquid to be deduced from the depth of immersion by reading a graduated scale.