ON  A  NEW  DENSIMETER. 
135 
Lastly,  Gerhardt  has  published  several  analyses  of  chloro- 
platinate  of  strychnine,  in  which  the  carbon  is  1  per  cent,  too 
high  and  the  nitrogen  0-5  per  cent,  too  low  for  the  admitted 
formula,  but  which  agree  perfectly  with 
C44H22N2Q4# 
This  is  rendered  more  probable  by  the  fact  of  the  same  thing 
taking  place  with  other  bases. — Chem.  Cfaz.,  Oct.  15,  1858, 
from  Oomptes  Mendus,  July  12,  1858. 
MODE  OF  PREPARING  LIQUIDS  OF  GIVEN  SPECIFIC  GRAVITY 
WITHOUT  CALCULATION  OR  PREVIOUS  TRIALS. 
Densimeter  by  M.  Spacowsky. 
In  the  laboratory  and  in  the  arts,  we  are  often  required  to 
prepare  a  definite  mixture  of  two  liquids,  such  as  sulphuric  acid 
and  water,  alcohol  and  water,  &c,  one  of  two  modes  is  generally 
employed.  1st,  Given  the  quantity  and  specific  gravity  of  one 
of  the  liquids,  the  quantity  of  the  other  liquid  is  calculated. 
This  mode  is  not  always  practicable,  requires  time,  and,  for  alco- 
holic liquids  especially,  the  concentration  or  mixture  gives  rise 
to  difficulties  frequently  insurmountable  ;  or  secondly,  areome- 
ters are  floated  in  the  liquors  ;  but  this  means,  which  is  very 
practicable  and  very  much  used,  presents  great  difficulties  in 
manufacture,  owing  to  the  various  temperatures  of  the  mixtures. 
A  densimeter  of  a  new  form  constructed  by  M.  Spacowsky, 
of  St.  Petersburg,  allows  the  preparation  of  a  liquid  mixture 
with  great  ease  and  precision,  and  without  a  thermometer. 
The  apparatus  consists  of  a  vessel  or  areometer  of  platina. 
This  areometer  is  closed  above  by  a  very  thin  partition  or  me- 
tallic plate,  such  as  that  employed  in  the  arenoid  barometers, 
and  yielding  to  the  slightest  pressure.  At  its  lower  end  the  areo- 
meter is  terminated  by  a  tube  furnished  with  a  stop-cock.  It  is 
suspended  by  a  piatina  wire  from  one  arm  of  a  delicate  balance, 
and  equilibriated  by  a  weight  suspended  also  by  a  platina  wire 
from  the  other  arm.  The  equilibrium  thus  established  will  evi- 
dently be  destroyed  if  the  areometer  and  the  counter-balancing 
weight  be  plunged  in  a  liquid  of  the  same  specific  gravity  ag 
that  which  it  contains ;  and  as  the  thin  partition  allows  the 
