Page:Theophrastus - History of Stones - Hill (1774).djvu/207

 LXXX. All thee Stones are found in the River Tmolus; their Texture is mooth, and like that of Pebbles; their Figure broad, not round; and their Bignes twice that of the common larger Sort of Pebbles. In their Ue in the Trial of Metals, there is a Difference in Power between their upper Surface, which has lain toward the Sun, and their under, which has been to the Earth, the upper performing its Office the more nicely; and this is cononant to Reaon, as the upper Part is the dryer; for the Humidity of the other Surface hinders its receiving o well the Particles of the Metals: For the ame Reaon alo it does not perform its Office o well in hot Weather