334 plint's natueal history. [Book XXXVL 



tained, that the depth of water in that river is not less than 

 that of the river Nilus. 



The obelisk that was erected by the late Emperor Augustus 

 in the Great Circus/ was originally quarried by order of King 

 Semenpserteus/ in whose reign it was that Pythagoras'' visited 

 Egypt. It is eighty-five feet^ and three quarters in height, 

 exclusive of the base, which is a part of the same stone. The 

 one that he erected in the Campus Martins, is nine feet less in 

 height, and was originally made by order of Sesothis. They 

 are both of them covered with inscriptions, which interpret 

 the operations of Nature according to the philosophy of the 

 Egyptians. 



CHAP. 15. (10.) — THE OBELISK WHICH SERVES AS A DIAL IN THE 

 CAMPUS MAHTIUS. 



The one that has been erected in the Campus Martins^ has 

 been applied to a singular purpose by the late Emperor 

 Augustus ; that of marking the shadows projected by the sun, 

 and so measuring the length of the days and nights. With this 

 object, a stone pavement was laid, the extreme length of 

 which corresponded exactly with the length of the shadow 

 thrown by the obelisk at the sixth hour^^ on the day of the winter 

 solstice. After this period, the shadow would go on, day by 

 day, gradually decreasing, and then again^^ would as gradually 

 increase, correspondingly with certain lines of brass that were 

 inserted in the stone ; a device well deserving to be known, 

 and due to the ingenuity of Eacundus ISTovus, the mathema- 

 tician. Upon the apex of the obelisk he placed a gilded 

 ball, in order that the shadow of the summit might be con- 



5 Or Circus Maximus ; in the Eleventh Region of the City. Accord- 

 ing to Kircher, it was this ohelisk that Pope Sextus V. had disinterred, 

 aud placed before the church of the Madonna del Popolo. 



^ There are sixteen various readings to this name. 



■^ Diogenes Laertius says that he arrived in Egypt in the reign of King 

 Amasis. 



s Boscovich and Brotero would read here ^' eighty -two feet and three 

 quarters," which is more in accordance with its height, as measured by 

 Kircher. 



^ After being long buried in ruins, it was disinterred, but not re-erected, 

 by Pope Benedict XIV. When tlius brought to light, it was found to be 

 broken asunder. On it there was an inscription stating that the Emperor 

 Augustus had " presented it to the Sun" — " Soli donum dedit." 



^" Twelve o'clock in the day. ^^ After the summer solstice. 



