After the completion of the Barberini Triton, it quickly became clear that a cistern would be needed to collect the water returning from the fountain. This water would then be piped to “private individuals”. In April of 1644 the council purchased a room that was under the houce belonging to Nicolo Soderini.
During the construction of the reservoir, it was suggested to place a horse trough, to accompany the ornamental fountain, as was typical, since the troughs were equivalent to that of gas stations today. Bernini planned a trough for the same corner as the cistern. The design was a stunning bi-valve shell, where the horizontal half would collect the water which was disgorged by three bees sculpted against the open part of the shell, which also had the inscription that you can still see stating, “Urban VIII Pont. Max., having built a fountain for the public ornamentation of the City [i.e. the Triton], also built this little fountain to be of service to private citizens. In the year 1644, XXI of his pontificate."
An interesting detail about the date is that Bernini put “XXII” instead of “XXI”, which was not totally true. The Fountain was inaugurated in June of 1644, so it was still the 21st year of Urban’s pontificate; which did not end until August of 1644.
Here is a unique description of the event as described by a diarist, “This month, June, a fountain was made at Capo le Case, in the square that used to be called after Duke Sforza, whose residence now belongs to the Barberini family. [The fountain] is in an angle giving onto the church of Trinità de' Monti. It was Cavalier Bernino the architect who had it made; in the inscription, he had it written that Pope Urban had built it in the XXII year of his pontificate, which 22nd year had not yet arrived but was only just over a month away. Someone stuck a piece of paper on the inscription, with the proverb: 'Better to be blind than to make a guess.’” This was such a contested fact that Cardinel Barberino actually sent a stonecutter to remove one of the figures leaving it as “XXI”, almost as if he did not want the Pope to have his 22nd year.
Apart from this spiteful story, the Pope did die on July 29th, eight days before his 22nd year. This led to the insightful statement “that the Barberini had robbed the whole world and now they even wanted to rob time."