far as the statue of Marcus Aurelius. Whether this had any connection with the aqueduct, or what its object was, is at present not known. The Plan and Section of the Aqueducts at the Claudium which is also at the end of the arches of Nero, on the Cœlian Hill, the point from which the water was divided into three branches, have been partially shewn in this work, but this could not be done completely until the explorations were made in 1875 and 1876. Subsidiary springs were continually used for the old aqueducts, that no water might be lost that could be used. Of these springs two were found in the space indicated in this Plan, one under part of the garden of Baron Hoffman, near the Navicella, the other under the garden of the monks of SS. John and Paul, in the cave or old stone-quarry which was formerly called a _vivarium_, but which really was a reservoir of the old aqueducts, and this is the most copious spring of the two. It seems almost certain that the water from both these springs found its way into the Colosseum, after the great excavations were made there in 1874-75. To get rid of this water is now (in 1876) a great object. The Government and the Municipality propose, at an enormous expense, to make a new drain from the Colosseum to the Tiber at a great depth. Careful enquiries have been made of the workmen employed in repairing the original drain of the time of Sylla and Scaurus; it was found in a very bad state, and the workmen were afraid to go along it without putting a wooden centering under the old vault, as they were made to fear lest the earth should fall in behind them. This was done for the whole length of the Colosseum, nearly as far as the Arch of Constantine, but the men were then obliged to give up this examination of it for want of air. They state that the main body of the water appeared to come in from under the road from the Navicella, and to run in a continuous stream as if from an aqueduct, and not to bubble up out of the earth as in a spring. This led to the exploration shewn in Plate XXXVI., to ascertain where the water came from[214]. The two springs above mentioned are both on a much higher level than the Colosseum, as will be seen by the Section; and as both are good drinking water, always fresh, it is certain that they must each have some outlet, or they would soon be stagnant and putrid. Every probability seems in favour of these being the springs that supply the inundation of the Colosseum, and if they could be turned off in another direction, as suggested in this Plan, the chief difficulty would be removed. A steam-engine would soon pump the water out, if it did not come in again. The so-called _vivarium_, under the Claudium, is marked on the excellent map of Nolli, in the eighteenth century, as a reservoir for water, which probably had been true; there are three small reservoirs there now which might easily have been united, and the whole be filled by closing the outlet.