THE 
AMERICAN  JOURNAL  OF  PHARMACY, 
NOVEMBER,  187  2. 
ON  A  NEW  APPLICATION  OF  TUBE  HYDROMETERS. 
By  Wilson  H.  Pile,  M.  D. 
In  an  article  read  before  the  American  Pharmaceutical  Association 
in  Baltimore,  1870,  I  endeavored  to  render  intelligible  a  new  method 
by  which  the  relation  between  the  degrees  of  Beaume's  hydrometer 
and  specific  gravity  could  be  easily  determined ;  and,  as  the  method 
there  pointed  out  is  intimately  connected  with  the  present  subject,  I 
will  briefly  recapitulate  the  main  points. 
A  plain  cylindrical  tube  of  thin  glass,  closed  at  its  lower  end,  is  to- 
be  immersed  in  pure  water,  at  a  temperature  of  60°  F.,  and  then 
loaded  by  pouring  in  shot  or  mercury  until  it  sinks  about  §  of  its 
length  in  the  water,  the  point  to  which  the  surface  of  the  water 
rises  being  then  marked  on  the  tube.  If  now  that  part  of  the  tube 
which  was  immersed  in  the  water  be  divided  into  145  parts,  and  these 
parts  numbered  from  the  top  downwards,  the  tube  will  represent  a 
Beaume"s  hydrometer  for  liquids  heavier  than  water,  and  by  floating 
it  in  any  liquid  of  greater  density  than  water,  its  degree  will  be  seen 
on  the  tube  at  the  surface  of  the  liquid. 
These  degrees  can  be  marked  on  paper,  and  the  paper  inserted  in 
the  tube  and  pushed  down  to  the  bottom,  the  upper  mark  or  zero  be- 
ing exactly  opposite  the  mark  which  had  been  previously  made  on  the 
tube. 
We  will  now  proceed  to  show  a  new  application  of  these  tube  hydro- 
meters in  determining  densities. 
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