Purification of the Acid if Lemons, 45 



Lemon juice feparated from all the mucous matter which falls down by cxpofure to the 

 contaft of the air for a few hours, that is to fay, fuch as it ought to be for ufe in medicine 

 or the arts, marks five degrees of denfity by the areometer for falts of Baume (fpeclfic gra- 

 vity 1.034). One hundred pounds of this juice require for faturation fix pounds four 

 ounces of calcareous carbonate. The citrate of lime, after being well waflied and dried, 

 weighs twenty pounds. 



One pound of pure cryftallized acid of lemons diflblved in a fufficient quantity of water, 

 demands one pound of carbonate of lime for its faturation. In this experiment the weight 

 of calcareous citrate has diminifhed the mafs rather more than one-fourth part, inftead of 

 increafing it upwards of two-thirds, as in the foregoing combination. Whence it may be 

 concluded, that one hundred pounds of lemon juice faithfully prepared, and of the ftrength 

 of five degrees by Baume's areometer for falts, contain fix, pounds four ounces of pure 

 concrete acid. This ferves to explain two phenemena } that is to fay, the increafe of i jibs. 

 20Z. in the calcareous citrate from lemon juice, and the prefence of mucilaginous matter 

 diflblved in that liquid, which enters into the combination of the calcareous citrate, and is 

 afterwards decompofed by the excefs of fulphuric acid neceflary to be added when that 

 citrate is decompofed. 



One ounce of diftilled water diflblves an ounce and two drams of citric acid, and pro- 

 duces 13 degree* (K») of cold by the folution. A like quantity of diftilled water diflolves 

 twice its weight of this acid, when it is heated to 80 degrees, or the boiling temperature. 

 One hundred parts of citric acid diflblved in a fuflicient quantity of diftilled water, boiling 

 hot, diflTolve 50 parts of calcareous citrate. 



A lemonade of the moft agreeable tafte and appearance may be had by diflblving 40 

 grains of citric acid in a pint of water, with the addition of a fufficient quantity of pure 

 fugar. It may be rendered fragrant by diflblving a fmall quantity of oleo-faccharum, pre- 

 pared by rubbing a lemon on a lump of fugar. The fugar imbibes the volatile oil of the 

 lemon, and renders it foluble. It is eafy by this means to preferve the whole of the vo- 

 latile oil of a number of lemons. The oleo-faccharum thus obtained may be mixed in a 

 mortar with a fufficient quantity of fugar. The mixture is then to be. dried by a gentle 

 heat, and preferved in well clofed glafs veflels. This method of procuring the flavour of 

 lemons at all times is preferable to employing the volatile oil obtained by diftillation. The 

 aftion of fire communicates to this laft an acrid flavour, eafily diftinguiffied by a delicate 

 tafte. 



I {hall finlfli my obfervations by enumerating fomc of the chara£lers of this acid, when ^ 

 mixed with different earthy and metallic folutions. , 



Solutions of the acetites of magnefia, lime, alumine, of the muriates of barytes, lime, 

 alumine, and magnefia, and of the nitrates and fulphates of thefe fame fubftances, ,do not . 

 undergo any change by the prefence of the citric acid. 



The muriates and nitrates of zinc, the fulphate, muriate, nitratCj and^acetite of copper, 



but, on the other hand, if his inference be corrcft, the furplus muft he a definite quantity, namely, fufficient . 

 to deftroy the mucilage. The difference of weight in the citrates fermed by tlie crude and the purified acids 

 with equal dofes of lime, as mentioned in a fubfequent parsgraph, may arife either from the prefence of mu- 

 cilage in the former acid, or a change of affinity for lime produced by the re-aftion of the excefs of fulphuric 

 »cid on the latter : but experiment mull determine which. M . 



iind 



