34 



without distillation. Hippocrates describes the pro- 

 cess of that operation ; talks of vapours arising from 

 the boiling fluid, which meeting with resistance stop 

 and condense, till they fall in drops from the body 

 to which before they clung in the form of vapours. 

 And Zosimus of Panopolis, not only desires his 

 students to furnish themselves with alembics,but gives 

 them directions how to use them, and places before 

 their eyes draughts of such as best deserve to be em- 

 ployed in practice. 



9. To proceed to other particulars of general chy. 

 rnistry ; the ancients among other things were ac- 

 quainted with lixivial salt, or sal alcali, one of the 

 prime principles of bodies. Sal alcali means properly 

 the salt extracted by fire from the Egyptian plant 

 kali, but as it is extracted also from other vegetables 

 though in less quantity, chymists extend the name 

 to all those salts, which like that of this plant, at- 

 tract and imbibe acids, arid by their contexture pe. 

 netrate into them, and closely unite with them. These 

 salts are termed promiscuously lixivial salt, sal al- 

 cali, rock salt, &c. It is of them Aristotle speaks, 

 when he says that in Umbria the burnt ashes of 

 Tushes and reeds, boiled in water, yield a great quan- 

 tity of salt. Theophrastus observes the same of 

 Umbria. Varro relates, that some who dwell on the 

 borders of the Rhine, having neither sea nor pit 

 salt, supply themselves with it by means of the sa- 

 line cinders of burnt plants. Piiny assures us, that 

 ashes are impregnated with salts, and speaks in par- 

 ticular of the nitrous ashes of burnt oak ; adding, 

 that these salts are used in medicine, and that a dose of 

 lixivial ashes is an excellent remedy. In short, Hip- 

 pocrates, Celsus, Dioscorides, and especially Galen, 

 often recommend the medical use of sal alcali ; and 

 their writings arc filled with passages, which shew 

 that they all understood it. To the mixture of acida 

 and alcali it was, that Plato ascribed fermentation ; 



