ANCIENT METHODS OF FILTRATION 499 



funnel inserted in the neck of a flask. The method thus clearly por- 

 trayed is called destlllatio per lacinias, and is evidently regarded as a 

 process of distillation ; ordinary filtration through porous stones and 

 through bibulous paper is treated in another and following chapter, 



Libavius makes reference to *' Ilippocrates's Sleeves," * by which 

 name were designated conical felt bags used in filtration. 



Sir Robert Boyle, in his " Experiments touching the Spring of the 

 Air," writes as follows : " Some learned mathematicians have of late 

 ingeniously endeavored to reduce filters to siphons, but still the true 

 cause of the ascension of water and other liquors, both in siphons and 

 in filtration, [requires] a clearer discovery and explication."! And in 

 another place he gives this " explication " : " The parts of the filter 

 that touch the water being swelled by the ingress of it to their pores 

 are thereby made to lift up the water till it touch the superior parts 

 of the filter that are almost contiguous to them ; by which means, 

 these being also wetted and swelled, raise the water to the other 

 neighboring parts of the filter till it have reached the top of it, Avhence 

 its own gravity will make it descend." J 



These passages can only apply to anethisis, which was apparently 

 a common method of filtration in Boyle's day. 



Again, to trace this process still later, Juncker, in his " Conspec- 

 tus Chemiae," published in 1730, describes seven kinds of filtration. 

 These differ chiefly in respect to the materials used : two methods, how- 

 ever, are essentially distinct ; the one is styled ^'■filtratio per chartam 

 bibulam . . . infimdihxdovitreo'''' (filtration through bibulous paper 

 in a glass funnel), and the other is described in the words '■'■per seg- 

 tnentum pannl lanei vel laciniani hombycinmn vel funicidos gossypiV'* 

 (through shreds of woolen cloth, silken threads, or through little 

 strings of cotton). 



Our friend Professor S. A. Lattimore sends us another reference to 

 this process from " The Laboratory or School of Arts, etc., compiled 

 by G. Smith, sixth edition, London, 1799" (vol. i., p. 435) ; the passage 

 is as follows : 



" To separate Water from Wine. — Put into the cask a wick of cot- 

 ton, which should soak in the wine by one end and come out of the 

 cask at the bung-hole by the other ; and every drop of water which 

 may happen to be mixed with the wine will still out by that wick or 

 filter." 



Thus we see that, so recently as the close of the last century, ane- 

 thisis was accounted a practical method of filtration. 



* The origin of this curious term we have been unable to discover, nor is it of common 

 occurrence in early writings on chemistry and pharmacy. The only explanation of the 

 expression which we have as yet found occurs in the " Lexicon novum Mcdicum Groeco- 

 Latinxm" of Stephen Blancardus, published in 1702. This author writes as follows: 

 '^Manica Hippocrath est sacculus laneus figura pyramidali, quo vina aromatica et medi- 

 camentosa, aliique liquores percolantur ; ex Stto snb et /cepow/tt m/.scco." 



\ Boyle's Works, London, 111% vol. i., p. 79. % Idem., vol. iii., p. 233. 



