368 
Spirit  of  Nitrous  Ether. 
f  Am.  Jour.  Pharm. 
\       July,  1877. 
remained  in  solution,  then,  upon  diluting  the  concentrated  spirit  with 
fractional   portions  of  stronger  alcohol,  the  volume  of  crude  ether 
separated  should  be  correspondingly  reduced.  That  this  is  the  case  is 
shown  in  the  following  table  : 
Quantity  of 
concentrated 
spirit  used, 
cc. 
Quantity  of 
stronger  al- 
cohol added, 
cc. 
Quantity  of 
satur't'd  sol. 
chloride  of 
calcium  used 
cc. 
Calculated  Results. 
Actual 
Results. 
Volume  of 
crude  ether, 
cc. 
Percentage 
of 
crude  ether, 
Volume  of 
crude  ether. 
Percentage  of 
crude  ether. 
IO'O 
20"0 
0'882 
16-82 
0-850 
16*50 
7-5 
20"0 
0'437 
iz-37 
0-450 
12*50 
6-o 
4-0 
20'0 
O'ICjO 
9'9° 
0'200 
io-oo 
5*o 
5"o 
20'0 
0"025 
8-25 
0-050 
8-50 
These  results  are  satisfactory  evidence  that  the  product  of  the  U. 
S.  P.  may  contain  five  per  cent,  of  "  crude  nitrous  ether,"  and  that 
when  a  sufficiently  concentrated  alcoholic  solution  of  nitrous  ether  is 
agitated  with  two  volumes  of  saturated  solution  of  chloride  of  calcium, 
B.  P.,  eight  per  cent,  of  such  crude  ether  as  is  separated  from  the  sur- 
face remains  in  solution.  It  becomes  evident,  also,  that  if  the  distillate 
of  the  U.  S.  P.  is  not  diluted  beyond  one-half  of  the  full  quantity  of 
spirit  intended  to  be  obtained,  the  method  may  be  applied  to  secure  a 
uniform  product. 
There  remained  one  other  point  to  be  determined  in  connection  with 
the  test  of  the  Br.  Ph.,  /.  in  what  respect  any  accidental  deviation 
in  the  strength  of  the  solution  of  chloride  of  calcium  may  affect  the 
result.  The  well-known  hygroscopic  character  of  chloride  of  calcium, 
and  the  tenacity  with  which  it  retains  water,  make  it  difficult  to  obtain 
and  retain  the  salt  uniformly  of  the  same  composition.  The  Br.  Ph. 
states  that  chloride  of  calcium  "  may  be  formed  by  neutralizing  hydro- 
chloric acid  with  carbonate  of  lime,  adding  a  little  solution  of  chlor- 
inated lime  and  slaked  lime  to  the  solution,  filtering,  evaporating  until 
it  becomes  solid,  and  finally  drying  the  salt  at  about  4000."  Four 
ounces  (avoir.)  of  this  salt,  dissolved  in  five  fluid  ounces  (Imp.  meas.) 
of  distilled  water,  constitute  the  saturated  solution  of  chloride  of 
calcium  of  the  Br.  Ph.  It  is  evident,  that  according  to  the  greater  or 
less  care  observed  in  the  preparation  and  preservation  of  the  salt,  the 
solution  will  vary  in  the  absolute  quantity  of  CaCl  contained  in  it,  and, 
