The architectural details of the Colosseum are much admired by architects; the cornice-mouldings of the lower storey are good examples of the style of the latter part of the first century[179]. The supply of water for the naval fights must have been from the Aqueducts; the water was brought from the Cœlian in a shallow channel, carried upon a lofty double colonnade, or arcade[180]. It has been mentioned[181] that there are slight remains of three reservoirs to receive it, which can be traced by remains of the particular cement used only for the aqueducts[182]. The continuations of the shallow channel along the corridors can be seen in many places, and are shewn in the photographs[183]. In the upper storey of the third century, on the exterior, the corbels for the masts to rest upon, and the holes in the cornice for them to pass through, have been mentioned[184]. On the interior of this wall, now that it has been stripped of plaster, and the wooden gallery that had been built up against it has been destroyed, we see clearly how hastily it has been built of old materials[185]. In other parts it has been cased with modern brickwork, but the corbels for fastening the masts on the inside are preserved[186]. THE EVIDENCE OF THE CONSTRUCTION, AND COMPARISON. It is well known that the first principle of the modern science of archæology is comparison. To compare small remains of one place with more perfect remains of the same kind, and as far as may be, of the same period, in other places. By these means, what has been destroyed in one is frequently supplied by the corresponding part in another. This is remarkably the case with regard to the amphitheatres, which are very numerous; there was one to every Roman town of importance, and such large buildings have almost invariably left remains visible[187]. It appears nearly certain that the Colosseum in Rome was the earliest, and that this was the type generally followed more or less closely by the others. This was a gradual development, and not merely one original design; the magnificent front and stone corridors of the Flavian emperors, which constitute what is usually considered to be the amphitheatre, were in fact built round a theatre previously existing[188]; that the names of theatre or amphitheatre were used indifferently is implied in many instances, and is distinctly shewn by an inscription found in the Colosseum itself, and preserved on the spot, in which it is called _theatrum_, and not _amphitheatrum_[189]. The theatre, or amphitheatre, round which the corridors were built, has been shewn to have been in parts of the time of Nero[190], and other parts earlier, most probably the work of Scaurus in the time of Sylla[191]. This colossal building was finished and consecrated by Titus in the year 80[192]. CAPUA.