Of Simpls Earths. ’ 13 tute. In the proportion of 20 or 30 per cent. u generally diminifhes, and when in a greater proportion extinguilhes, the charadter of filice- ous earth . to this obfervation there are very fevv exceptions. 5. Siliceous earths, in a ftony or fandy form, are remarkable for their hardnefs, tranfparency, an uftre ; but^ their power of communicating thefe properties is inferior to the powers of com. mumcatmn poffeflfed by the foregoing earths, 1 ex is exceedmgly comminuted, as it and fpungy PreCipitad ° n trom alkalis > « is light ScoitiJ7), or Stronthian Earth. This is a new earth, firft noticed as fuch, as tar as I can find, by Dr. Crawford, who fent me fubSi“ “ ' he >' Car 'WO- 1 l™ve fu.ee i U T t V anous ex P er >ments lately read to mav li/ a f 1 • Acadeni ) , > an account of which Mner I to* u"/*!?'' 1 from thu I aper I fele£t the following particulars : 1. It has hitherto been found only in a mild hereafr UnitC - tÜ ^ ! ° f thlS f P ecies 1 1111111 hereartei give a deicription. 2. Likc common limeftone it lofes its air in 2 n g heat, and then forms a lime. wa?er * 1 | mC l l much more foluble in c °™mor tamr^itriolnf 16 ’ , llke . ba D’tic, decompofe 5 . it