the world > matter > constitution of matter > density or solidity > [adjective] > relating to measurement of specific gravity > specific instruments for measuring
hydrometrical1780
hydrometric1828
pycnometric1898
1780 T. A. Mann in Philos. Trans. 1779 (Royal Soc.) 69 654 The hydrometrical principles laid down in this essay.
1807 P. Jonas (title) A Complete Set of Hydrometrical Tables.