354      SPIRIT  "0E  NITROUS  ETHER  AND  NITRITE  OF  SODA. 
ble  in  10  parts  of  boiling  and  35  parts  of  cold  water.  On  ana- 
lysis this  salt  gave  the  following  formula :    C42H22N2  04  ,As03  . 
The  author  believes  this  salt  deserves  a  place  among  well  de- 
fined salts,  and  therapeutically  it  must  be  uniform  in  its  action, 
owing  to  its  regular  composition. — Jour,  de  Pharmaeie,  Mai,  1865. 
ON  SPIRIT  OF  NITROUS  ETHER  AND  NITRITE  OF  SODA. 
By  Robert  Warrington,  F.R.S.,  F.C.S. 
The  spirit  of  nitrous  ether,  as  a  pharmaceutic  compound, 
dates  back  to  a  very  early  period.  In  the  thirteenth  century,  in 
the  writings  of  Raymond  Lully,  its  preparation  is  mentioned,  and 
two  hundred  years  afterwards  an  improved  process  for  making 
it  is  given  by  Basil  Valentine.  A  very  good  idea  of  the  nature 
of  these  old  processes,  and  of  the  curious  state  of  chemistry  a 
century  and  a  half  since,  may  be  obtained  by  perusing  the  "  Dis- 
pensatory "  of  Dr.  Bates  on  this  subject ;  the  second  edition  of 
which  work,  published  in  the  year  1700,  by  Dr.  Salmon,  imparts 
such  a  graphic  idea  of  the  state  of  the  manufacturing  processes 
of  pharmaceutic  chemistry  at  that  period,  and  the  curious  theo- 
ries and  quaint  explanations  of  chemical  action  then  current, 
that  I  feel  I  need  hardly  apologize  for  giving  the  account  in 
detail.  Dr.  Bates,  it  appears  from  the  preface,  "  was  Physician 
to  two  Kings  and  a  Protector,"  (Cromwell,  Charles  II.,  and 
James  II.)  In  order  to  clearly  understand  the  operation  of 
making  the  sweet  or  dulcified  spirit  of  nitre,  it  will  be  better 
that  we  should  commence  with  the  process  for  the  spirit  of  nitre 
(nitric  acid)  employed.  Some  of  the  clauses  which  do  not  refer 
to  the  chemical  part  of  the  subject  have  been  omitted.  At 
p.  53,  we  have  "  Spiritus  nitri,  spirit  of  nitre.  Bates).  R  Sand 
p.  ij.  nitre  p.  j.  Mix  and  distil  by  a  retort  till  the  fumes  cease 
to  appear.  Salmon).  §  1.  Here  is  but  p.  ij  of  sand  to  p.  j  of 
nitre,  which  I  judge  too  little  ;  the  Colledge  in  their  Dispensa- 
tory allow  5  to  1,  as  you  may  see  in  our  Pharm.  Lond.  lib.  3, 
cap.  10,  sec.  47.  But  three  to  one  is  by  experience  found  to  be 
;  the  best  proportion.  §  2.  R  Pure  nitre  lb.  ij  :  common  bole,  or 
potter's  earth,  lb.  vj.  Mix,  and  put  them  into  a  large  earthern 
or  glass  retort  luted,  set  it  in  a  close  reverberatory  furnace  fit* 
