ANCIENT METHODS OF FILTRATION. 497 



anethisis, a word made from dvd, " upward," and 7]di.aig, " a straining 

 off." A study of the chemical works of the middle ages further shows 

 that the expression " destillatio per Jiltrum " is invariably used to de- 

 scribe anethisis, while '\/iltratio " is applied to ordinary filtration. We 

 shall give quotations proving this, but first make brief reference to 

 early records. 



The ancient Egyptians portray in the rock-cut memorials the opera- 

 tion of filtration in connection with the manufacture of wine. Their 

 simple wine-press consisted of a bag in which the grapes were placed, 

 and squeezed by means of two poles turned in contrary directions. 

 Small colanders of bronze have been found at Thebes. Views of the 

 interior of an Egyptian kitchen, cut in the tomb of Rameses III. at 

 Thebes, represent siphons in use for drawing off liquids of various 

 kinds. (Wilkinson.) The ancient Romans employed strainers and 

 colanders {colum) made of a great variety of materials. Wine-strain- 

 ers were made of silver and bronze ; the poorer classes used linen, and, 

 where nicety was not required, they used those made of broom or of 

 rushes. Strictly speaking, however, percolation through colanders is 

 not filtration, for capillary action plays no part. 



It is interesting to note that the earliest mention of filtration which 

 a brief search has disclosed refers to the method we have ventured to 

 call anefhisis. This occurs in Plato's "Symposium," written about 

 four hundred years before the Christian era ; the passage is as fol- 

 lows : " Socrates then sitting down, observed, ' It would be well, 

 Agatho, if wisdom were a thing of such a kind as to flow from the 

 party filled with it to the one who is less so, when they touch each 

 other, like water in vessels running by means of a thread of wool from 

 the fuller vessel into the emptier.' " * 



Ai'istotle, the pupil of Plato, in his essay " De Generatione Ani- 

 malia," refers to the other process in the following words : " Flesh 

 is produced, therefore, through the veins and pores, the nutriment 

 being deduced in the same manner as water through earthen vessels 

 not sufficiently baked." 



This passage, together with others occurring in Plato, shows that 

 both systems of filtration were employed at that early period. 



Geber, whose clear description of anethisis we have quoted, was 

 followed by the celebrated Arabian physician, Rhazes ; he uses the 

 same expression, " destillatio per filtrum," in the following passage : 

 " Dissolve as much [common salt] as you wish in five times as much 

 warm soft water, and distill per filtrum and congeal [i. e., crystal- 

 lize]." f Rhazes died about 930 a. d. 



Among the early writers on alchemy, no one is oftener quoted than 

 Raymund Lulli, surnamed the Enlightened Doctor (born 1235, died 



* Plato's works, Burges's translation, vol. iii., p. 480 (Bohn). 



f " Collect, ex Rhasi in Margarita Pretiosa Novella " of Petrus Bonus (1330), Yene- 

 tia, 1546. 



VOL. XVI.— 32 



