110 
Solubility  of  Calcic  Hydrate. 
Am.  Jour.  Pharm. 
Feb.,  1884. 
foregoing  is  desirable,  so  as  to  imitate  the  condition  of  the  renal  excre- 
tion of  the  herbivora,  which  is  alkaline,  that  of  man  being  usually  acid. 
The  salt  is  very  soluble.  Fifty  grains  dissolve  in  thirty  minims  of 
water,  forming  a  syrupy  liquid.  The  dose  may  be  from  ten  to  fifteen 
grains. — Phar.  Jour,  and  Trans.,  Dec.  29,  1883. 
THE  SOLUBILITY  OF  CALCIC  HYDRATE  IN  WATER 
AT  DIFFERENT  TEMPERATURES. 
By  Thomas  Maben. 
Head  at  a  Meeting  of  the  North  British  Branch  of  the  Pharmaceutical 
Society,  December  19,  1883. 
In  the  course  of  an  able  paper  on  "  Lime  Water ;  its  Preparation, 
Preservation  and  Estimation/7  read  some  time  ago  by  Mr.  Abraham, 
of  Liverpool,  and  subsequently  published,1  the  author  stated  that  he 
had  found  a  difficulty  in  maintaining  his  lime  water  at  the  proper 
strength.  On  investigating  the  cause  of  this  he  was  led  to  the  conclu- 
sion that  the  difference  was  due  to  increase  of  temperature,  and  he 
indicated  that  the  solubility  of  calcic  hydrate  fell  from  0*56  grain  CaO 
per  fluidounce  at  60 °F.  to  something  like  0*5  grain  at  70°F. 
Having  had  occasion  in  July  last  to  give  a  few  notes  (which  were 
afterwards  published  in  an  extended  form2)  on  the  same  subject  before 
a  local  association,  I  undertook  at  that  time  an  investigation  as  to  the 
effect  of  temperature  on  solubility,  and  though  my  experiments  were 
confirmatory  of  Mr.  Abraham's  to  a  certain  extent,  the  results  did  not 
show  such  a  marked  difference  as  his  had  done.  I  have  recently 
repeated  these  experiments  with  more  care  than  before,  and  now 
bring  the  results  before  you,  in  the  hope  that  they  may  prove  of  some 
interest. 
I  have  been  much  surprised,  in  looking  into  various  authorities,  to 
find  that  great  differences  of  opinion  prevail  regarding  the  solubility 
of  calcic  hydrate.  A  few  of  these  may  be  noted.  At  15°C.  calcic 
hydrate  is  held  in  solution  to  the  extent  of  1  part  CaO  in  781  parts 
water,  according  to  Squire ;  780  (Miller  and  Bineau) ;  778  (Dalton)  • 
776  (Paris  Codex);  764(Hager);  750  (United  States  Pharmacopoeia); 
1  u  Pharm.  Journal"  [3],  xiii,  p.  433. 
2  "  Chemist  and  Druggist,"  1883,  p.  390. 
