Both Uses of

equivalent
in
Ulysses, by James Joyce

Here the listener who was none other than the Scotch student, a little fume of a fellow, blond as tow, congratulated in the liveliest fashion with the young gentleman and, interrupting the narrative at a salient point, having desired his visavis with a polite beck to have the obligingness to pass him a flagon of cordial waters at the same time by a questioning poise of the head (a whole century of polite breeding had not achieved so nice a gesture) to which was united an equivalent but contrary balance of the bottle asked the narrator as plainly as was ever done in words if he might treat him with a cup of it.†
Chpt 14 *

Conscious that the human organism, normally capable of sustaining an atmospheric pressure of 19 tons, when elevated to a considerable altitude in the terrestrial atmosphere suffered with arithmetical progression of intensity, according as the line of demarcation between troposphere and stratosphere was approximated from nasal hemorrhage, impeded respiration and vertigo, when proposing this problem for solution, he had conjectured as a working hypothesis which could not be proved impossible that a more adaptable and differently anatomically constructed race of beings might subsist otherwise under Martian, Mercurial, Veneral, Jovian, Saturnian, Neptunian or Uranian sufficient and equivalent co†
Chpt 17

Definition:

being equal or essentially equal