Bloom is correct that "Capillary attraction is a natural phenomenon," but as an explanation of sexual ejaculation, much less a justification of it, nothing could be more ludicrous. This is one in a series of flimsy excuses that he dreams up in Circe to account for why he masturbated in the woods near the Poulaphouca waterfall. Being surrounded by plants, he supposes, could somehow have made semen rise mechanically in his penis.

Capillary attraction (or capillary action, capillarity, wicking) is the natural phenomenon of liquids pulling themselves through narrow tubes by a mix of physical forces: adhesion (the tendency of the molecules to adhere to a solid surface like the walls of the tube), cohesion (their tendency to adhere to one another), and surface tension (their tendency, drawn together by cohesion, to form a kind of tight elastic skin on their surface). In narrow spaces (the Latin word capillus means "hair") these forces can overcome the pull of gravity, drawing water far up to the leaves of a plant through its xylem tubes, which are mere microns wide. (The theoretical limit of such tiny columns of water, approached but not reached in sequoia trees, is about 120 meters—past that the weight of all the water will overcome the capillary forces.)

At the Poulaphouca falls Bloom withdrew into the shade of some yew trees, in summertime, with flowers blooming. He tries out the theory that, with sap rising in all the plants around him, perhaps his own juices were simply joining in all the sympathetic "attraction." Here the hallucinatory logic of Circe exaggerates his amateur scientism to absurd lengths.

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John Hunt 2025

Capillary attraction and repulsion, with concave lines demonstrating the effect of adhesion. Source: chem.libretexts.org.

Capillary action varying by the width of tubes. Source: www.designingbuildings.co.uk.

Water being drawn up through a plant's xylem to replace the water lost in the process of photosynthesis. Source: www.nagwa.com.