372    Solubility  of  Plumbic  Chloride  in  Glycerin.  {A\*™lwA™~ 
weighed  with  the  usual  precautions.  The  following  were  the  results 
of  two  determinations : 
Solubility  of  PbCl2in 
Used.  PbS04  found.    100  of  C!3H803.  Average. 
I  .  .  .    274-59  6  07  2-01 
II.  .  .    385-85  8-18  1-97 
1-995 
The  solubility  of  the  plumbic  chloride  appears  not  to  be  perceptibly 
increased  by  the  temperature  at  which  the  experiments  were  per- 
formed, since  after  several  days  standing  in  the  cold  (always  in  a 
desiccator),  only  the  slightest  possible  opalescence  was  noticeable  ; 
the  advantages  gained  by  heating  being  the  diminished  viscidity  of 
the  glycerin,  and  the  prevention  of  the  absorption  of  moisture. 
For  the  second,  weighed  quantities  of  dry  glycerin  were  mixed 
with  weighed  quantities  of  distilled  water  in  specific  proportions. 
The  bottles  containing  the  mixtures,  with  an  excess  of  plumbic  chlo- 
ride, were  intermittently  shaken  for  about  a  week  ;  these  experiments 
being  conducted  at  the  ordinary  temperature.  The  results  show  that 
the  solubility  of  the  plumbic  chloride  is  in  direct  ratio  to  the  propor- 
tions of  the  glycerin  and  water.    Thus  : — 
Mixture  A.    C3H803,  50  per  cent.  +  H20,  50  per  cent. 
PbS04        Solubility  per 
Used.         found.  cent. 
I  .  .  .    371-60       5-55  1-37       Theory,  1-363. 
II.  .  .    389-48       5-35  1-26       Practice  average,  1-32.. 
Mixture  B.    C3H803,  25  per  cent.  +  H20,  75  per  cent. 
PbS04        Solubility  per 
Used.         found.  cent. 
I  .  .  .    307-88       3-39  1-01      Theory,  1-044. 
II.  .  .    418-43       4-87  1-06      Practice  average,  1-036. 
Mixture  C.    C3H803,  12-5  per  cent.  +  H20,  87'5  per  cent. 
Used.  PbS04  found.       Solubility  per  cent. 
453-39  4-43  0-91  |  theory,  0;888* 
[  Practice,0-91. 
In  calculating  the  solubility  of  plumbic  chloride  in  these  mixtures, 
I  have  taken  its  solubility  in  pure  water  to  be  0-733  per  cent.  By 
adding  together,  the  weight  of  the  plumbic  chloride  dissolved  by  the 
quantity  of  glycerin  present  in  100  parts  of  the  mixture  (as  deter- 
mined from  the  experiments  with  pure  glycerin),  and  that  dissolved 
by  the  water,  I  obtained  the  theoretical  amount  which  the  mixture 
