368 plint's natueal histoet. [Book XXXVI. 



CHAP. 44. STONE OF SIPHNOS. SOFT STONES. 



At Siphnos," there is a kind of stone^* which is hollowed 

 and turned in the lathe, for making cooking-utensils and ves- 

 sels for keeping provisions ; a thing too, that, to my own know- 

 ledge,^^ is done with the green stone^® of Comum^'^ in Italy. 

 "With reference, however, to the stone of Siphnos, it is a sin- 

 gular fact, that, when heated in oil, though naturally very soft, 

 it becomes hard and black ; so great a difference is there in 

 the qualities of stone. 



There are some remarkable instances, too, beyond the Alps, of 

 the natural softness of some kinds of stone. In the province 

 of the Belgae, there is a white stone^^ which admits of being cut 

 with the saw that is used for wood, and with greater facility 

 even. This stone is used as a substitute for roof-tiles and 

 gutter-tiles, and even for the kind of roofing known as the 

 pavonaceous^^ style, if that is preferred. Such are the stones 

 that admit of being cut into thin slabs. 



CHAP. 45. SPECITLAK STONES. 



As to specular-" stone — for this, too, is ranked as one of the 

 stones — it admits of being divided with still greater facility, 

 and can be split into leaves as thin as may be desired. The 

 province of Nearer Spain used formerly to be the only one 

 that furnished it — not, indeed, the whole of that country, but 

 a district extending for a hundred miles around the city of 

 Segobrica."^ But at the present day, Cyprus, Cappadocia, and 

 Sicily, supply us with it ; and, still more recently, it has been 

 discovered in Africa : they are all, however, looked upon as 

 inferior to the stone which comes from Spain. The sheets 



13 See B. iv. cc. 22, 23. 



1* Ajasson identifies it with Ollar stone, talc, or soap-stone, a hydrous 

 silicate of magnesia, and nearly allied to the Ophites of Chapters 11 and 30. 



15 He being a native of that part of Italy. 



16 The Green Colubine Ollar stonej or soap-stone of Italy. 

 " SeeB. iii. c. 21. 



IS Identified by Brotero with our Free-stone or grit-stone. 



1^ So called from its resemblance to the spots on a peacock's tail. He 

 alludes, probably, to the mode of roofing with tiles cut in the form of 

 scales, still much employed on the continent, and in Switzerland more 

 particularly. 



20 Or " Mirror-stone," Transparent Selenite or gypsum ; a sulphate of 

 lime. 



