This study aims to investigate the poetics of the deployed transience of Inert Gas Series/Helium, Neon, Argon, Krypton, Xenon/From a Measured Volume to Indefinite Expansion, by Robert Barry (1969). This work consisted of the release of gases from their containers into the atmosphere in different places in California, which was announced by means of a white poster disclosing the details of a postal address and a telephone number that, when dialed, played an answering machine recording with its description. This leads to a temporal dimension that debates between the fugacity of the performative gesture and the infinity of what it conceptually implies, that problematizes immateriality and displaces the plastic values towards values that are implicit in the idea of the work as a conceptual exercise. But what does the total dematerialization of the work support imply? What is it that the Inert Gas Series tries to show by referring to time, and what is the importance of art, as a concept, to articulate an idea of magnitude in the work? This research seeks to answer such questions from the premise that Barry’s work, as an immaterial, temporal and conceptual proposal, manages to present a series of paradoxes around art that articulate a poetic of transience, which is tested by comparison with other examples (Rachel Whiteread, Oscar Muñoz, and Olafur Eliasson). Finally, the poetics of transience exhibits the impossibility of retaining the passing of time by means of plastic devices that are proposed as a flow, that is, they represent the spatial/material change in time.