[146] Frontinus did not live to see this completed. [147] Cap. 86, 91, 92, and 105. [148] These are at present almost hid by modern houses built up against them, but it is expected that these modern erections will shortly be removed. The remains of the bridge project at a right angle from the palace of Domitian. It had the aqueduct at the top at a very high level, and a road for horses by the side of it at a lower level, as at the Ponte Lupo, Ponte S. Antonio, and other bridges of the aqueducts. [149] These imperial “Edicts” or “Decrees,” or Laws and Constitutions, have been published in various works. The later ones relating to this subject are published by Polenus, in the Appendix to his edition of Frontinus, 4to. Pataviæ, 1722; and by Rondelet, as a supplement to Frontinus, who had published those issued up to his time. See Commentaire de Frontin sur les aqueducs de Rome, 2 parts, 4to. and atlas folio, Paris, 1802; and Rondelet, Opere, 6 vols. 4to. Mantova, 1841, tom. vi. p. 117, &c. [150] This water was celebrated for its coolness, as mentioned in the life of Alexander Severus by Lampridius, c. 30. [151] The new company for bringing these springs into Rome again, under the name of the Aqua Marcia-Pia, has been obliged to make compensation to the town of Tivoli for the possible injury to the manufactories established there, which depend upon the force of the water, although the damage was in a great degree imaginary. This new aqueduct brings the water of the Marcia only. The water is nearly of the same quality as that of the Claudia, and is still found as cool as it was in the time of the early Empire, notwithstanding that it is brought into Rome in metal pipes for the last ten miles. A number of shops for the sale of this cool water have been opened in different parts of Rome. Nature never changes, and the same qualities of particular springs which prevailed two thousand years ago, prevail still. It is said by persons who have witnessed the experiment tried, that in the hot summer weather of Italy, when the thermometer of Fahrenheit stands above 100, the contrast between the heat of the air and the coldness of the water is so great that if a glass tumbler is suddenly put into the water near its source, the glass will break in the same manner as a glass tumbler will break in England if boiling water is poured into it in frosty weather. [152] In the above the _m_ = to the Roman mile = 1,000 Roman passus. _p_ = to the Roman passus = 5 Roman feet. The Roman mile (_mille passus_) = 1,618 English yards. The Roman passus = 4 English feet 10·428 inches. The Roman foot = 11·6496 English inches. [153] The Roman foot was nearly as long as our own, being, according to the most accurate estimate, about 11½ English inches (11.6496). [154] Frontinus, c. 24.