DURING THE MIDDLE AGE. 15.3, 



th.it it was ncccffary to burn calcareous carth r 

 before it could be employed in making mortar. 

 In the Pharmacopoeia of Schroeder we meet with, ' 

 Cnl\ viva and Lixivium Culcis, commonly cal- 

 led Lime-water. Clay was iliflinguifhed from 

 fand, bur not according to its genuine cha- 

 racter ; and various kinds of Hones were defin- 

 ed in the fame fuperficial manner. Fine and 

 coloured earths were iludioufly fought for the 

 purpyfes of medicine ; and that the genuine, 

 might not be confounded with the fpurious, 

 they were inclofcd on the fpot that produced 

 tliem, and fcalcd by the governor or chief ma- 

 gin rate; from whom they palled into the fnops 

 of the apothecaries. 



Among the phlogillic bodies, they were ac- 

 quainted with Sulphur and its Flowers; and L. 

 Valentinus mentions a iblution of it in iixcd al- 

 kali, and Bcguiiuis dcfcribes it as diflblvcd in 

 volatile alkali. Vigcncrus fufpccled that it was 

 compofcd of phlogifton and vitriolic acid. Kf- 

 fcntiul oils were very early di/Hllcd, as well as. 

 philofophic and cmpyrcumatic, from undluous 

 fublhinccs, but with a flrongcr fire. Beccher 

 difcovcred the vitriolic acid dulcified with fpi- 

 rits of wine. B. Valentinus mentions the Vi- 

 triolic and Nitrous ^Ethers but very (lightly. 

 Crollius however has tranfmitted very diflindly 

 tbe art of preparing the former. The analyfis of 

 Soot was attempted by Vigcneru-*. Of thclc 



v.*ho ' 



