Calling out the hours seems to have been first practised after the erection of city gates, and, in my opinion, to have taken its rise in Germany; though indeed it must be allowed that such a regulation would have been very useful in ancient Rome, where there were no clocks, and where people had nothing in their houses to announce the hours in the night-time. During the day people could know the hours after water-clocks had been constructed at the public expense, and placed in open buildings erected in various parts of the city. The case seems to have been the same in Greece; and rich families kept particular servants both male and female, whose business it was to announce to their masters and mistresses certain periods of the day, as pointed out by the city clocks. These servants consisted principally of boys and young girls, the latter being destined to attend on the ladies. It appears, however, that in the course of time water-clocks were kept also in the palaces of the great: at any rate Trimalchio, the celebrated voluptuary mentioned in Petronius, had one in his dining-room, and a servant stationed near it to proclaim the progress of the hours, that his master might know how much of his lifetime was spent; for he did not wish to lose a single moment without enjoying pleasure. I have not read everything that has been written by others on the division of time among the ancients; but after the researches I have made, I must confess that I do not know whether the hours were announced in the night-time to those who wished and had occasion to know them. There were then no clocks which struck the hours, as has been already said; and as water-clocks were both scarce and expensive, they could not be procured by labouring people, to whom it was of most importance to be acquainted with the progress of time[458]. It would therefore have been a useful and necessary regulation to have caused the watchmen in the streets to proclaim the hours, which they could have known from the public water-clocks, by blowing a horn, or by calling out.