Am.  Jour.  Pharm. 
Oct.,  1883. 
Chemistry  of  Tartaric  and  Citric  Acid. 
509 
Table  II. — Determinations  of  i^ree  and  Precipitable  Acid  hi  Concen- 
trated Lemon  and  other  Juices. 
Specific 
gravity 
Acid,  reckoned  as  citric 
(ozs.  per  gallon). 
•Precipitable 
lor 
100  of  free 
acid. 
of  juice. 
Free  acid. 
Precipitable 
acid. 
1-235 
61-2 
63-4 
103-6 
64-8 
61-9 
yo  o 
1-241 
02-1 
61-6 
99-2 
1-240 
65-8 
59-7 
90-7 
64-9 
55-7 
OO  O 
1-235 
47-9 
48-5 
101-4 
1*235 
52-3 
49-9 
uO  1 
1-237 
50-1 
49-3 
98-4 
1-326 
108-3 
99-8 
92-2 
1-205 
59-2 
53-9 
91-1 
1-400 
16-8 
11-6 
69-0 
1-350 
11-7 
8-0 
68-4 
Lemon  juice- 
Highest  
Lowest  
Mean  of  895  pipes 
Sample  A  
B  
Bergamot  juice- 
Highest  
Lowest  
Mean  of  90  pipes.. 
Lime  juice — 
Sample  A  
B  
Orange  juice — 
Sample  A  
Sample  B  
There  are  only  two  analyses  of  concentrated  Lime  juice;  both  show 
a  distinctly  low  proportion  of  precipitable  acid,  a  result  confirmatory 
of  the  analyses  already  published  ("Chem.  Soc.  J./'  1875,  936). 
The  two  specimens  of  concentrated  Orange  juice  show,  as  we  should 
expect,  a  very  small  amount  of  free  acid.  This  acid  is  also  to  a  con- 
siderable extent  not  citric,  the  acid  precipitable  as  calcium  salt  bearing 
a  smaller  proportion  to  the  free  acid  than  in  any  of  the  other  juices 
analyzed. 
The  figures  in  the  table  clearly  show  that  specific  gravity  is  no  guide 
to  the  value  of  juice.  All  lemon  juice  is  brought  as  nearly  as  possible 
to  the  standard  gravity  of  1*24  for  the  purposes  of  sale. 
Influence  of  Heat  on  Solutions  of  Tartaric  Acid. 
That  crystallized  tartaric  acid  when  fused  at  170°  is  converted  into 
