82         Recent  Literature  Relating  to  Pharmacy.  {AFebJruUaryT?9oom" 
BOILING    POINT    OF  MIXED  LIQUIDS. 
J.  K.  Haywood,  J.  Phys.  Chem.,  1899,  3,  317. 
Previous  investigations  were  carried  out  by  measuring  the  vapor 
pressure  with  varying  composition,  the  temperature  being  kept  con- 
stant. The  author  considered  it  more  profitable  to  proceed  as  in 
actual  practice ;  he,  therefore,  examined  the  variation  of  the  boiling 
point  under  constant  pressure.  This  method  had  previously  been 
adopted  by  Thayer  Phys.  Chan.,  1898,  2,  382;  1899,  j,  36). 
The  apparatus  used  was  essentially  that  of  OrndorfT  and  Cameron 
(Am.  Chem.  J.,  1895,  17,  517).  The  materials  employed  were  care- 
fully purified ;  the  thermometer  graduated  to  ^  of  a  degree  was 
carefully  calibrated  and  all  readings  are  uncorrected.  Three  diagrams 
are  given.  These  contain  a  number  of  carefully  plotted  curves, 
which  may  be  studied  with  profit,  by  referring  to  the  original 
article. 
From  the  results  of  his  investigations  the  author  has  drawn  the 
following  conclusions  : 
(1)  All  mixtures  of  the  following  pairs  of  liquids  boil  at  tempera- 
tures between  the  boiling  points  of  the  constituents  :  alcohol-water, 
alcohol-ether,  chloroform-carbon  tetrachloride,  acetone-water  and 
acetone-ether. 
(2)  A  solution  containing  17-5  per  cent,  ot  alcohol  in  carbon 
tetrachloride  distils  without  change  at  65-5°  C,  approximately, 
under  768-4  millimetres  pressure. 
(3)  A  solution  containing  12-5  per  cent,  of  methyl  alcohol  in 
chloroform  distils  without  change  at  540  C,  approximately,  under 
770-2  millimetres  pressure. 
(4)  A  solution  containing  from  12-13  per  cent,  of  methyl  alcohol 
in  acetone  distils  without  change  at  55-9°  C,  approximately,  under 
764-8  millimetres  pressure. 
(5)  A  solution  containing  from  15  -20  per  cent,  of  carbon  tetra- 
chloride in  acetone  distils  without  change  at  a  temperature  but 
0-05°  below  that  of  pure  acetone,  and  all  mixtures  containing  more 
than  40  per  cent,  of  acetone  boil  within  i°  of  the  boiling  point  of 
acetone  itself. 
(6)  The  close  proximity  of  the  boiling  points  of  the  constituents 
appears  to  be  a  favorable  condition  for  the  existence  of  a  maximum 
or  a  minimum  point  on  the  boiling  point  curve.  Similarity  of  con- 
stitution, however,  seems  to  be  a  strongly  modifying  condition. 
