But one keyed instrument was known to the ancients. That was a form of organ, in effect and appearance not very dissimilar to a small portable modern organ, with one bank of keys. Its mechanism, however, was very different in respect to the construction of the pipe stops and bellows. In particular, the steady flow of air to the pipes was obtained from the pressure of water, and a receptacle partly filled with water was an essential part of every Roman organ. From this feature it was called the water-organ. The Emperor Nero had been a notable performer on the water-organ and had interested himself in some improvements in its mechanism. As with the modern organ, so with the Roman water-organ, the sonorous, sustained and resonant notes lent themselves naturally to the expression of religious emotion. Religious emotions, Brinnaria, at this period of her life, felt to an overwhelming extent. She expressed them in long colloquies with Numisia and Causidiena, in a tendency to be unnecessarily careful about her duties, to pet her daily routine, as it were; and in an awakening to the charms of music in general and of organ music in particular. She developed into a capable performer on the water-organ, bought for herself the finest to be found in all Rome, had it set up in the Atrium in place of the old one which had belonged to the order of Vestals, and sat before it for hours at a time. Her solitary communings with her favorite instrument became her chief solace when she was: low-spirited, which was seldom, and her favorite diversion when she was high-spirited, which was often. Moreover, her rendition of well-known airs and he improvisings came to be a great pleasure to all the inmates of the Atrium, most of all to Causidiena. Besides her many duties and her indoor amusements, Brinnaria found time for much activity outside the Atrium. She had kept up her girlish friendship for the sieve-maker Truttidius, and saw him occasionally, sometimes ordering her litter halted before his shop and leaning out to ask after his health and that of his family. Truttidius had an ailing household, though he himself was always well and never seemed to get any older. From her talks with Truttidius she came to take a personal interest in the welfare of the countless tenants in her many properties in the poorer quarters of the city. She visited some of them-a sort of approach to modern slumming by the philanthropic rich. Such actions on the part of a landowner and such an attitude of mind from any rich person toward the poor was very unusual in the ancient world. Her behavior in this regard won Brinnaria a sort of fame among the poor, as if she were a live goddess moving among them.