I can however produce from a contemporary writer, a strong proof that Pliny alluded here to a fire-engine, and I do not find that the passage has been before quoted. Apollodorus, the architect, who was employed by the emperor Trajan in constructing the celebrated bridge over the Danube, and erecting some large works at Rome, and who was put to death by his successor Adrian, out of revenge for a jeering answer which he received from him, as we are told by Dio Cassius, describes in the fragment of his book on warlike machines, how assistance may be given when the upper part of a building is on fire, and the machine called _sipho_ is not at hand. In this case leathern bags filled with water are to be fastened to long pipes in such a manner, that by pressing the bags the water may be forced through the pipes to the place which is in flames[587]. The _sipho_, therefore, was a machine by which water might be easily projected to a considerable height, to extinguish a place on fire that could not be reached by any other means. That in the fourth century at least a fire-engine, properly so called, was understood under the term _sipho_, is fully proved by Hesychius, and also by Isidorus, who lived in the beginning of the seventh century[588]. As the latter remarks that such engines were employed in the East for extinguishing fires, there is reason to conclude that they were not then used in the west. The question still remains, at what time this apparatus for extinguishing fires was introduced at Rome. From the numerous ordinances for preventing accidents by fire, and in regard to extinguishing fires, which occur in the Roman laws[589], there is reason to conjecture that this capital was not unprovided with those useful implements and machines, of the want of which in a provincial town Pliny complains, and which he himself had supplied. This conjecture, however, I am not able to prove; and instances both in ancient and modern times show that the good police establishments of small towns are not always to be found in capitals. Antioch and several other towns were provided with lanterns, which were wanting even in the proud Rome. But what excites some doubt is, that fire-engines are never mentioned in the numerous accounts given of the fires which took place in that city. At present it is impossible to speak of a misfortune of this kind without stating whether a sufficient number of engines were assembled, and what they effected, as Pliny has not failed to do in his short account of the fire at Nicomedia.