226 
A  Plea  f 07'  Minim  Measuring. 
r  Am.  Jour.  Pharm. 
t      May,  1881. 
temperature  below  60°  the  table  can  be  extended  to  any  desired  point. 
In  order  to  determine  the  specific  gravity  of  the  liquid  at  the  points 
noted  we  have  merely  to  divide  its  specific  gravity  at  60°  by  the  num- 
ber of  volumes  occupied  at  the  observed  temperatures,  as  shoAvn  by 
the  table,  and  multiply  the  quotient  by  1,000. 
In  experimenting  with  glycerin  the  dilatation  was  observ^ed  to  be 
2 J  volumes  for  every  10  degrees  of  temperature,  this  expansion  being 
uniform  as  high  as  100°,  the  limit  of  the  examination.  The  con- 
traction on  cooling  down  to  40°  was  likewise  in  the  same  ratio,  as  will 
be  seen  in  the  following  table: 
Temperature. 
Volume. 
Spec.  Gray. 
Spec.  Grav.  of  30='B. 
40° 
995 
1-260 
1-267 
50° 
997-5 
•  1-257 
1-264 
60° 
1000 
1-254 
1-260 
70° 
1002-5 
1-250 
1-257 
80° 
1005 
1-247 
1-254 
90° 
1007-5 
1-244 
1-251 
100° 
1010 
1-241 
1-248 
The  specific  gravity  of  the  sample  used  was  found  to  be  at  60°, 
1*254  or  29f°B.,  and  annexed  is  given  the  specific  gravities  of  glyce- 
rin of  30°B.,  which  is  the  strength  of  the  article  of  commerce,  or  at 
least  is  so  represented  to  be.  By  referring  to  such  a  table  we  would 
be  able  to  use  the  hydrometer  at  any  temperature  without  the  trouble 
of  reducing  at  the  time  of  every  trial,  which  is  of  considerable  diffi- 
culty during  the  summer  months.  Tables  so  prepared,  representing 
various  chemical  products  would,  no  doubt,  prove  of  considerable  value 
to  the  pharmacist  and  also  to  the  manufacturing  chemist. 
A  PLEA  FOR  MINIM  MEASURING. 
By  Thos.  C.  Craig,  M.D. 
Much  has  been  written  in  regard  to  the  size  and  the  number  of 
drops  of  different  liquids  in  a  definite  measure. 
Almost  all  observers  are  at  variance  with  each  other  in  reg^ard  to 
the  ultimate  results  obtained — some  claiming  a  certain  number  of  drops 
equal  to  a  fluidrachm,  others  differing  and  declaring  that  it  takes  a 
greater  or  less  number,  as  the  case  may  be,  of  drops  to  make  a  fluid- 
drachm,  while  each  observer  has  used  analogous  liquids. 
We  are  told  that  the  number  of  drops  to  the  fluidrachm  will  vary 
in  bottles  with  lips  of  different  lengths,  that  the  width  of  the  bottle 
