364  Spirit  of  Nitrous  Ether.  { Arr  ju^rI^>7h7arm' 
6o°  F.,  be  376  grains.  By  dividing  this  weight  by  that  of  a  fluidounce 
of  water  we  again  obtain  the  correct  specific  gravity,  if  no  condensation 
has  occurred  : 
455  659  :  376  : :  1  :  0*825,  the  calculated  specific  gravity  of  the  spirit  of  nitrous  ether. 
Upon  now  taking  the  specific  gravities  of  these  two  spirits,  by  the 
aid  of  an  accurate  1000-grain  bottle,  they  were  found  to  tally  exactly 
with  the  calculated  specific  gravities  : 
The  concentrated  spirit,  at  6o°  F.,  weighed  843  grains. 
The  spirit  of  nitrous  ether,  at  6o°  F.,  weighed         825  grains, 
indicating  specific  gravities  respectively  of  0*843  anc*  °'825}  and  prov- 
ing that  no  condensation  occurs  when  alcohol  and  nitrous  ether  (in  concen- 
trated solution)  are  mixed. 
The  second  question  may  therefore  be  answered  as  follows  : 
1.  The  specific  gravity  of  spirit  of  nitrous  ether,  U.  S.  P.,  is  not  correctly 
stated. 
2.  Its  specific  gravity,  if  it  contains  5  per  cent,  of  pure  nitrous  ether, 
should  be  0*8235. 
3.  In  the  experiments  made  the  spe:ific  gravity  varied  between  0*822  and 
0825. 
III.     Is  THE   PERCENTAGE   OF   NITROUS   ETHER    IN    THE    SPIRIT  OF 
NITROUS   ETHER  OF   THE   "  PHARMACOPOEIA  "  CORRECTLY  STATED? 
The  discovery  of  the  error  in  the  pharmacopceial  statement  of  the 
specific  gravity  prompted  me  to  inquire  into  the  correctness  of  the 
statement  of  the  strength  of  the  spirit  of  nitrous  ether.  The  "  Phar- 
macopoeia "  states  very  positively  that  it  "contains  five  per  cent,  of 
its  peculiar  ether."  In  the  Table  H  it  has  already  been  foreshadowed 
that  this  cannot  be  true,  if  by  "  its  peculiar  ether  "  it  is  meant  to 
designate  "absolute  nitrous  ether,"  and  this  is  plainly  demonstrated  by 
the  following  calculation  : 
4|  troyounces  (=  2160  grains)  of  nitric  acid,  sp.  gr.  1 -42,  contains  1620  grains 
(—  75  per  cent.)  HON05. 
63  grainsof  HONOs  are  capableof  forming  75  grainsof  C4H5ONOs, 
and,  consequently,  1620  grains  of  HONOs  can  form  1928*5  grains  of 
C4H6ONOa. 
The  specific  gravity  of  absolute  nitrous  ether  is  stated  to  be  0*947  ; 
consequently  a   fluidounce  of  nitrous  ether,  at  6o°F.,  will  weigh 
