It would be needless to attempt by measurement to attain such minute accuracy as this; as it must in fairness be stated that it is extremely difficult to ascertain minute differences in the present state of the remains. Where two stones or steps are _in situ_, the one over the other, it is very easy to measure the distance from the face of the one to the face of the other; but when, as in this instance, we are dependent on the weather-marks or a position assumed from the details of other examples, we must be content with approximations, and without the guidance of some system of definite proportions can never be sure we are right. The determination of this point was so essential that I have carefully measured all the angle and roofing stones I could get access to in the Museum, and find that, as nearly as can be ascertained, the dimension of 17 inches is correct; but the longer one is, it may be, 2/10ths—it may be 3/10ths—of an inch in excess. Any one can verify this for himself; but I am so convinced of its correctness by my measurements, that I shall use the longer step as a dimension of 21 Greek, or 21·2625 English, inches. Assuming this for the present, the next thing that suggests itself is, that 21 inches is the acknowledged length of the Babylonian cubit. We know that after the captivity, the Jews added a handbreadth to their cubit, so as to make it up to this then fashionable measure; and as we know that Caria had been so long under the domination of the Persians, ruling from Babylon, there is no _à priori_ improbability in this measure being current there.[9] The well known tablets at Mylassa, given in Böckh, prove incontestably that Mausolus acknowledged himself a satrap of Artaxerxes as late as 355, or only two years before his death. If it is contended that he afterwards emancipated himself from the Persian yoke—of which there is no proof—it is by no means clear that he did not commence his own tomb himself some time before his death. At least it is nearly certain that no other man ever had a tomb of any great magnificence who did not in his lifetime take measures to secure its erection.