} 
292  Chemical  Notes.  jun'l'im.''"' 
Incompatibles. 
If  other  ingredidnts  have  to  be  added  to  an  emulsion,  the  following 
rules  are  to  be  observed  : 
1.  Never  add  to  an  emulsion  hot  liquids.  This  rule  is  important 
when,  instead  of  water,  the  emulsion  has  to  be  made  with  an  infusion 
or  deeoction,  such  liquids  must  be  allowed  to  cool  perfectly  before 
using  them. 
2.  When  sugar,  syrup,  extracts,  acids,  salts,  alcohol  and  ethereal 
liquids  have  to  be  added,  tlie  emulsion  is  to  be  diluted  previously  to 
the  fullest  extent  possible.  Among  the  salts,  the  lead  and  iron  salts 
require  the  most  caution.  Acids,  tinctures,  especially  those  made  with 
strong  alcohol  and  spirit  of  nitrous  ether,  are  first  diluted  with  water 
before  adding  them  to  emulsions.  Borax  added  to  an  emulsion  made 
with  gum  arabic  coagulates  with  the  gum  to  a  thick  paste.  A  suffi- 
cient quantity  of  sugar  or  syrup  will  dissolve  it  again. 
The  most  difficidt  addition  to  an  emulsion  is  tincture  of  chloride  of 
iron.  By  diluting,  however,  both  the  tincture  and  the  emulsion  to  the 
fullest  extent  possible  and  then  adding  the  diluted  tincture  in  small 
quantities  at  a  time,  even  this  can  be  added. 
CHEMICAL  NOTES. 
By  Prof.  Samuel  P.  Sadtler,  Ph.D. 
Inorganic  Chemistry. — Supposed  Existence  of  Ice  at  High  Tem- 
peratures.— In  the  February  number  of  this  journal  (p.  58),  we  noted 
the  striking  experiments  of  Dr.  Thomas  Carnelley  on  the  conditions 
of  fusion  of  ice,  from  which  it  appears  that  when  the  pressure  in  the 
flask  was  reduced  below  the  point  of  critical  pressm^e  (4*6  mm.  for 
ice),  no  application  of  heat  sufficed  to  melt  the  ice.  Dr.  Carnelley 
drew  from  this  the  conclusion  that  the  ice,  under  this  condition,  could 
really  be  heated  far  beyond  its  ordinary  fusing-point.  Prof.  Lothar 
Meyer,  of  Tubingen,  and  J.  B.  Hannay,  of  Glasgow,  have  recently 
given,  independently  of  each  other,  what  seems  to  be  the  truer  expla- 
nation of  this  phenomenon.  They  both  show  by  crucial  tests  that  the 
ice  at  no  time  becomes  hotter  than  the  temperature  of  the  body  of  the 
flask  or  receiver,  in  the  neck  of  which  the  thermometer-bulb  projects^ 
which  must  be  below  zero;  so  that  when  the  pressure  is  reduced 
below  the  critical  jioijit  (4*6  mm.),  ice  will  volatilize  without  melting, 
