Preparation of the Citric Acid, 113 



it depofit mucilage, and puts it into a ftate of being pre- 

 served. I obferved nothing of this kind ; nor was I furprifed 

 on that account, as mucilage and extractive matter are not of 

 a nature to be feparated by fuch means. The latter, in parti- 

 cular, is not among the number of thofe which, forming a 

 pellicle, abandon their folvent in confequence of the infoTu- 

 bility they acquire by becoming fatu rated with oxygen. 

 Lemon juice thus prepared will keep well, no doubt; but 

 where ? In our cellars, and not in the hold of a (hip proceed- 

 ing towards the equinoctial. 



It is cuftomary, as I have been informed by Don Her- 

 nandez, to boil the lemon juice pretty ftrongly before it is 

 put on board; but, befides the burnt fmell it contracts, it 

 ferments dill in the bottles, and makes them burft when the 

 fhips approach the line. 



II. The concentration of lemon juice by congelation, pro- 

 pofed by Georgi, is attended with no better fuccefs. It brings? 

 it to the confidence of fyrup from being a more powerful 

 acid, efpecially if it be reduced to one-eighth of its volume. 

 But this procefs neither deftroys the mucilage nor the ex- 

 tract; and befides, its not being practicable in the countries 

 where the lemon tree grows, becaufe it is a native of hot 

 climates, it may be readily conceived that this fyrup will not 

 Hand the heat experienced in fea voyages any more than that 

 prepared by means of fire. 



III. Dr. Brugnatelli announces that lemon juice diluted 

 in fpirit *of wine frees itfelf in the courfe of a few days from 

 part of its mucilaginous matter; and he adds, that, after the 

 alcohol has been feparated by diftillation, the acid is ob- 

 tained as pure as it is when concentrated. It may be readily 

 believed that by this procefs the object is not entirely ac- 

 complished ; for I mould afk the author, what has become 

 of the extractive part found by Scheele in lemon juice ? 



I was defirous of trying whether it was poffible to render 

 it pure by means of charcoal powder, fo much extolled, and 

 which has given occafion to fo much difpute in Germany; 

 but I found that this procefs was attended with no real effect. 



It follows from this review, that, except the formula of 

 Scheele, no method has yet been found of feparating the 

 mucilage and extractive fubftance of^e mons, and that we 

 rauft adhere to it until a fimpler one <^nl be difcovered. 



IV. Lemon juice, evaporated to the confiftence of fyrup, 

 and diluted in feven or eight times its volume of fpirit of 

 wine, becomes turbid, and depofits a matter fomewhat 

 browniih, clammy, and which diflblves completely in water. 

 This is pure mucilage. 



This fpiritous mixture, diftiHed in a retort, leaves th$ 

 Vol. X. H juice 



