m  SPECIFIC  GRAVITY  OF  ALCOHOL. 
209 
is  tedious,  as  it  strongly  retains  some  turpentine,  which,  though, 
faintly,  may  be  smelt  in  the  chloroform  solution.  This  solution, 
on  standing  a  day,  separated  some  white  scum  like  cream  aboye 
the  milk ;  by  this  observation  I  was  induced  to  try  another  way 
for  preparing  a  light  and  clear  solution,  and  was  successful  with 
the  following  very  simple  process :  One  part  of  the  best  com- 
mercial gutta  percha  was  cut  into  small  pieces,  and  by  agitation 
dissolved  in  12  parts  of  chloroform  ;  on  standing  for  a  day  all 
the  coloring  matter  rises  like  scum  to  the  surface,  leaving  the 
solution  as  clear  as  Br.  Geiseler's  ;  this  may  then  be  easily  drawn 
off  to  the  last  drop.  A  wide  glass  tube,  narrower  on  the  bottom, 
and  so  arranged  that  both  ends  may  be  closed  by  corks,  is  the 
only  instrument  necessary ;  after  the  separation  is  complete,  the 
upper  cork  must  be  removed  and  the  lower  one  loosened,  so  as 
to  allow  the  liquid  to  run  out  slowly ;  thus  prepared,  the  only 
loss  will  be  some  chloroform,  which  is  insignificant  when  com- 
pared with  the  loss  of  material  and  time  of  Dr.  Geiseler's  method. 
The  advantages  of  this  solution  over  collodion  consist  in  the  ab- 
sence of  the  contractile  power  and  gloss  of  the  latter,  and  in  the 
close  resemblance  to  the  skin,  in  appearance  and  elasticity. 
New  York,  March,  1856. 
REMARKS  ON  THE  UNITED  STATES  STANDARD  OF  SPECIFIC 
GRAVITY  FOR  INDICATING  THE  STRENGTH  OF  ALCOHOL, 
AND  ON  THE  OFFICIAL  HYDROMETER. 
South  Boston,  Feb.  8th,  1856. 
Mr.  W.  Procter,  Jr. 
Dear  Sik, — My  attention  has  been  directed  to  an  article  on 
the  strength  of  certain  acids  and  alcohol,  by  A.  P.  Sharp,  pub- 
lished in  the  Proceedings  of  the  American  Pharmaceutical  Asso- 
ciation. The  instruments  in  use  here,  I  think,  are  not  constructed 
by  Trailer  tables,  as  published  in  lire's  Dictionary  of  Arts.  In 
view  of  the  uncertainty  of  strength  of  alcohol  as  an  article  oi 
commerce,  I  think  you  would  do  a  great  service  to  purchasers 
and  those  who  have  occasion  to  use  the  article,  if  you  would  pub- 
lish in  your  journal  the  U.  S.  standard  of  specific  gravity  for 
such  strengths  of  alcohol  as  are  in  common  use.  *  *  *  * 
If  there  be  any  standard  or  rule  based  on  the  action  of  Congress, 
14 
