This essay describes the emergence and stabilization in French and English experimental accounts, in second half of the seventeenth century, of the narrative sequence: X did (some process in the laboratory) and X saw (something happen), where X stands for a pronoun, I or we in English, je, nous or on in French. Focussing on the French case, it shows how the use of the collective pronoun on in the experimental accounts registered in the files of the Académie des Sciences is directly related to the will of this newly created institution to assert a collective authority on the production and legitimization of experimental matters-of-fact produced in the laboratory. It is argued, through the case of the discovery of the blind spot in the eye by Mariotte, that this new narrative form imbeds a construal of the experiment as a public spectacle, and of the proof as a witnessing event, which eludes the Academy's attempts to monopolize the process of fact validation and favors the diffusion and display of experiments in front of larger audiences. The question of whether a privileged witness such as the King of France who patronized the Academy could not have constituted by himself a suitable audience to ensure a full legitimization of experimental matters-of-fact while remaning within the bounds of academic practices is addressed. It is answered in the negative by providing evidence for the lack of interest of the absolute monarch in experiments. On the other hand, the outdoor practices of observation and measurement are shown to interfere in a constructive manner with the absolutist power and to capture the attention of the absolutist monarch, where laboratory experiments had failed. It is proposed that natural philosophers in the early modern period bear the burden of proof in buying credibility for the phenomena they try, by paying a tribute to the standing of the patrician elites that witness their experiments. This makes sense in a straightforward manner of the lack of interest of the King of France in a practice which exalts the power of the very group he is trying hard to control through the absolutist structure of power.