2*9 



The concentrated lemon juice from Sicily contains pretty uniformly 

 7-8 oz. per gallon of combined organic acid, equal to about 10 p c. of 

 the total organic acid (reckoned as citric) present. Of the total organic 

 acid about 10 p. c. is not precipitable as calcium s.ilt, and is therefore 

 not citric acid ; this proportion is, however, by no means constant. 

 Purchases of lemon juice are unfortunately still made on the basis of 

 acidity, and not on the amount of precipitable acid present. Analyses 

 of 895 pipes of concentrated lemon juice by Mr. Grrosjean have been 

 published (Town Cham. Soc. Lond. 43,333). The average proportion of 

 precipitable acid was 99-2 p. c. of the free acid, but the range of varia- 

 tion was considerable, individual parcels of juice giving 81.1, 85.8, and 

 103.6 of precipitable acid p. c. of free. 



Concentrated Bergamot juice has a similar sp. gr. to lemon juice, 

 but a lower acidity ; it generally contains frea acid equal to about 51 

 oz. of citric acid per gallon. The quantity of combined organic acid 

 is apparently similar to that in lemon juice, namely 7-8 oz. per gallon ; 

 but the proportion of combined to total is higher, 12-13 p. c. The 

 proportion of unprecipitable acid is about 13 p. c. of the total. Mr. 

 Grosjean's analyses of 90 pipes of Bergamot juice, show a mean of 98.4 

 of precipitable acid for 100 of acidity, the extremes being 95.4 and 

 101.4. 



The unconcentrated lime juice of Montserrat has a mean of sp. gr. 

 of 1.036 ; it contains according to Conroy (Ph. J. 1883, 606) an aver- 

 age of 7.84 p. c, or 12.54 oz. per gallon of free acid. The extremes 

 observed were 6.70-10.05 p. c, equal to 10.7-16.1 oz. per gallon. 

 The juice yields 0.43 p. c. of ash. It contains only a trace of sugar. 

 "VVarington found the combined acid in two samples 5 p. c. of the 

 total ; 10 p. c. of the total acid was not precipitable. 



Concentrated lime juice is a viscid liquid, sp. gr. 1.32, and with an 

 acidity averaging about 94 oz. of citric acid per gallon. The combined 

 acid is about 8-9 oz. per gallon. The unprecipitable acid is about 

 10.14 p. c. of the total. The precipitable acid bears a lower proportion 

 to the free than is the case with either lemon or bergamot juice, the 

 published analyses showing a mean of 93.8 of precipitable acid for 100 

 of free. 



The nature of the organic acid, other than citric, present in lemon, 

 bergamot, and lime juice has not been determined. A little formic acid 

 and acetic acid have been detected in concintrated juice , bat the prin- 

 cipal acids other than citric are clearly non-volatile and have soluble 

 calcium salts. The acids most probably present are malic and aconitic. 



Besides lemon juice, some crude calcium citric, prepared in Sicily by 

 precipitating lemon juice with chalk, is exported into England. It 

 contains about 64 p. c. of citric acid. 



Process of Manufacture. 



The manufacture of citric acid from concentrated lemon juice is ex- 

 tremely simple. A proper quantity of whiting (levigated chalk) is 

 mixed with water, and heated by steam in a wooden vat provided with 

 a revolving agitator; the concentrated juice is then slowly pumped in, 

 care being of course taken that the whiting is finally in small excess, 

 the liquor never becomes neutral, however long boiling may be con- 

 tinued, or however great is the excess of whiting present; the adjus - 

 ment of juice and whiting is therefore effected by ascertaining if the 



