As the _amphora_ was the standard measure of capacity for wine, the _metreta_ for oil, the _modius_ for grain, so the _libra_ was the standard measure of weight.[26] To insure honesty in trade they were examined periodically by order of the ædiles; those found _iniquæ_ (short) were broken, and their owners sentenced to banishment in remote islands. In A. D. 167, Junius Rusticus, prefect of the city, ordered a general inspection to be made in Rome and in the provinces; weights and measures found to be legal were marked or stamped with the legend "[Verified] by the authority of Q. Junius Rusticus, prefect of the city." These weights of Rusticus are discovered in hundreds in Roman excavations.[27] The original standards were kept in the Temple of Jupiter on the Capitol, and used only on extraordinary occasions. Official duplicates were deposited in other temples, like those of Castor and Pollux, Mars Ultor, Ops, and others, and kept at the disposal of the public, whence their name of _pondera publica_. Barracks and market-places were also furnished with them. The most important discovery connected with this branch of Roman administration was made at Tivoli in 1883, when three _mensæ ponderariæ_, almost perfect, were found in the portico or peribolos of the Temple of Hercules, adjoining the cathedral of S. Lorenzo. This wing of the portico is divided into compartments by means of projecting pilasters, and each recess is occupied by a marble table resting on "trapezophoroi" richly ornamented with symbols of Hercules and Bacchus, like the club and the thyrsus. Along the edge of two of the tables runs the inscription, "Made at the expense of Marcus Varenus Diphilus, president of the college of Hercules," while the third was erected at the expense of his wife Varena. The tables are perforated by holes of conical shape, varying in diameter from 200 to 380 millimetres. Brass measures of capacity were fastened into each hole, for use by buyers and sellers. They were used in a very ingenious way, both as dry and liquid measures. The person who had bought, for instance, half a modius of beans, or twenty-four _sextarii_ of wine, and wanted to ascertain whether he had been cheated in his bargain, would fill the receptacle to the proper line, then open the valve or spicket below, and transfer the tested contents again to his sack or flask.