AmbJe°c"ri8576arm' }  Contributions  from  the  School  of  Pharmacy,  etc.  537 
With  three  and  a  half  per  cent,  solution  of  metaphosphoric  acid: 
Four  cc  of  the  salt  solution- 
treated  with  1  cc.  of  the  meta- 
phosphoric acid : 
Barium  chlor.,  5  p.  c. 
Calcium  chlor.,  5  p.  c. 
"  "      1  p.  c. 
«      J  p.  c. 
Magnes.  sul.,  5  p.  c. 
Alumin.  sul.,  5  p.  c. 
Ferric  chlor.,  10  p.  c. 
«        "       5  p.  c. 
"        "       1  p.  c. 
"        "  tincture 
Ferrous  chlor.,  5  p.  c. 
Ferrous  sul.,  5  p.  c. 
"       "    1  p.  c. 
Lead  nitrate,  5  p.  c. 
"  "  1  p.  c. 
«       "      i  P.  c. 
Lead  acetate,  5  p.  c. 
1  p.  c. 
i  p.  c. 
Silver  nitrate,  5  p.  c. 
"        "      1  p.  c. 
No  pre. 
Resulting  precipi- 
tates dissolved 
by  adding: 
Precip. 
cc 
No  pre. 
Precip. 
No 
f  12  cc  meta.  ac. 
{     oriocc.  HC1 
5  cc.  meta.  ac. 
(  2  cc.  meta.  ac. 
\     1  cc.  HC1 
large  excess  HC1 
10  cc.  meta.  ac. 
1 '4  cc.  nitric  ac. 
2  cc.  meta.  ac. 
o'7  cc.  meta.  ac. 
5  cc.  meta.  ac. 
07  cc.  nitr.  ac. 
1  cc.  meta.  ac. 
0-4  cc.  meta.  ac. 
J  8  cc.  meta  ac. 
[  5  cc.  nitric  ac. 
In  1  cc.  salt  sol.  with  3  cc. 
metaphos.  ac. 
M  -a 
0*4  cc. 
0*4  cc. 
1*7  cc. 
2*0  CC. 
S"Sfi 
0-076  grm 
0*076  " 
0*307 
0*361 
I'o  cc  0-180 
o*5  cc.  0*090 
ro  cc.  o*i8o 
.2  ©  £ts 
o  •+<  o  £ 
«■;  o  cs 
74  P- 
74  ' 
292 
343 
171 
171 
With  the  ferric  chloride  tincture,  the  thick  white  precipitate  was 
only  made  gelatinous  by  addition  of  excess  of  the  metaphosphoric 
acid. 
In  production  of  metallic  precipitates,  the  sharpest  distinction  between 
the  phosphoric  acids  appears  to  be,  with  ferric  salts,  between  orthophos- 
phoric  acid  and  the  other  two.  Both  ferric  pyrophosphate  and  ferric 
metaphosphate  are  soluble  in  excess  of  their  respective  phosphoric 
acids,  if  in  water  solution,  but,  in  case  of  metaphosphate,  not  soluble 
in  the  alcoholic  solution  of  the  pharmacopoeial  tincture.  Lead  and 
silver  salts  are  precipitated  by  each  of  the  three  forms  of  phosphoric 
acid ;  the  lead  metaphosphate  being  soluble  in  excess  of  metaphos- 
phoric acid  (a  distinction  from  both  the  other  phosphoric  acids).  The 
