498 THE POPULAR SCIENCE MONTHLY. 



1315 A. D.). In his works we find the following characteristic pas- 

 sage : " Take, in the Name of God, great Bay Salt, as it is made out 

 of the Sea ; take a good quantity and stamp very small into a stone- 

 morter : then take Cucurbites of Glass and pour your Salt therein : 

 then take fair Well-water, and let your salt resolve into cleer water ; 

 being all dissolved then distil it by Filter ; that is to say, hang a jag 

 Felt or Woolen cloath in the Cucurbite ; and let the other end hang 

 in another Glass beside it, set as it were under it, that the water may 

 drop into it that the Felt or Cloath may draw out and that shall be 

 cleer as silver." 



This unmistakable description of anethisis occurs in the first chap- 

 ter of a booklet bearing the follow^ing title : " Philosophical and 

 Chymical Experiments of the Famous Philosopher Raymund LuUi 

 .... wherein is contained .... the admirable and perfect way of 

 making the great Stone of the Philosophers as ... . sometimes prac- 

 tised in England by Raymund Lulli in the time of King Edward the 

 Third." London, 1657. 



Thomas Aquinas, the eminent scholastic teacher of the thirteenth 

 century, who is best known by his theological and metaphysical works, 

 also paid some attention to scientific pursuits, possibly acquiring this 

 taste from his learned master, Albertus Magnus. Aquinas, or the di- 

 vine Thomas, as he was called by his admirers, defines distillation to 

 be the " purification of waters falling drop by drop, and effected by 

 placing a filter cut in the shape of an iron dart in the little dish con- 

 taining the water to be distilled." * 



Libavius, in his remarkable work, "Alchymia," sometimes called 

 the first text-book of chemistry (published in 1595), devotes two entire 

 chapters to the subjects of distillation and of filtration.f In the 

 fourteenth chapter he describes, with much attention to detail, the 

 manner of filtering by means of pieces of felt (lacinia) shaped like 

 an ox-tongue, the broader portion of which is placed in the vessel 

 containing the liquid to be filtered, and " the apex in the recipient, or, 

 if the vessel has a narrower neck, in a suitable funnel." This demon- 

 strates that the method was not resorted to on account of the want of 

 proper funnels, and suggests that perhaps a special virtue was attrib- 

 uted to a liquid thus purified. 



Libavius's work contains rude woodcuts illustrating different meth- 

 ods of procedure. For perfecting the purification a series of four 

 vessels was used. These were placed on steps, one above another, 

 and the liquid passed through a capillary siphon from the uppermost 

 to the one immediately below, and thence by another siphon to the 

 third vessel, and so on to the fourth. This series of vessels can be 

 inclosed in a glass-covered box for filtering volatile liquids. Another 

 woodcut represents the lower end of a capillary siphon hanging into a 



* "Pretiosa Margarita Novella " of Petrus Bonus (1330), Venetia, 1546. 

 f "Commeut. Alchymia," Part I., lib. iii., edition 1606. 



