The Collaborative International Dictionary
Haematachometer
Haematachometer \H[ae]m`a*ta*chom"e*ter\ (-t[.a]*k[o^]m"[-e]*t[~e]r), n. [H[ae]ma- + Gr. tachy`s swift + -meter.] (Physiol.) A form of apparatus (somewhat different from the hemadrometer) for measuring the velocity of the blood.
Wiktionary
haematachometer
n. (context dated English) An apparatus for measure the velocity of the blood.