296 SCIENCE IN SHORT CHAPTERS. 



TRAVERTINE. 



THE old exclamation about Augustus finding Rome of 

 brick and leaving it of marble, deceives many. Ancienc 

 Rome was by no means a marble city, although the quarries 

 of Massa and Carrara are not far distant. The staple- 

 building materials of the Imperial City, even in its palmi- 

 est days, were brick and travertine. The brick, however, 

 was very different from the porous cakes of crudely burnt 

 clay of which the modern metropolis of the world is built. 

 I have examined on the spot a great many specimens, and 

 found them all to be of remarkably compact structure, 

 somewhere between the material of modern terra-cotta and 

 that of common flower-pots, and similarly intermediate in 

 color. The Roman builders appear to have had no standard 

 size; the bricks vary even in the same building the Coli- 

 seum for example; all that I have seen are much thinner 

 than our bricks we should call them tiles. 



But the most characteristic material is the travertine. 

 The walls of the Coliseum are made up of a mixture of 

 this and the tiles above-mentioned. The same is the case 

 with most of the other very massive ruins, as the baths, etc, 

 Many of the temples with columns and facing of marble 

 have inner walls built of this mixture, while others are 

 entirely of travertine. 



I was greatly surprised at the wondrous imperishability 

 of this remarkable material. In buildings of whioh the 

 smooth crystalline marble had lost all its sharpness and 

 original' surface, this dirty, yellow, spongy-looking lime- 

 stone remained without the slightest indication of weather- 

 ing. A most remarkable instance of this is afforded by the 

 temple of Neptune at Paestum, in Calabria. This is the 

 most perfect ruin of a pure classic temple that now remains 

 in existence, and in my opinion is the finest. I prefer it 

 even to the Parthenon. 



We have a little sample of it in London. The Doric 

 columns at the entrance of the Euston station are copies of 

 those of its peristyle. The originals are of travertine, the 

 blocks forming them are laid upon each other without 



