396        EXAMINATION  OF  THE  SULPHATE  OF  QUINIA. 
chemical  perfection  of  the  salt,  are  even  less  accurate  than  the 
statements  they  propose  to  correct. 
In  view  of  this  unqualified  contradiction  of  my  remarks,  I 
have  been  obliged,  reluctantly,  to  take  the  time  and  trouble  of 
another  more  accurate  examination  of  the  sulphate  of  quinia  in 
question,  in  order  that  the  character  or  business  of  the  manu- 
facturers may  not  suffer  through  any  looseness  of  expression  or 
inaccuracy  of  mine  ;  and  in  order  to  repel  the  charge  in  the  sense 
in  which  it  appears  to  have  been  made. 
I  therefore  beg  the  favor  of  an  insertion  of  the  following 
paper  in  the  Journal ;  and  that  you  will  send  a  proof  impression 
of  it,  at  your  earliest  convenience,  to  Messrs.  Powers  &  Weight- 
man. 
Very  respectfully,  your  obed't.  serv't, 
E.  R.  Squibb. 
This  series  of  experiments  embraces  the  examination  of  fifteen 
bottles  of  this  commercial  sulphate  of  quinia,  taken  without 
selection  from  a  shelf  upon  which  some  forty  or  fifty  bottles  still 
remain. 
Experiment  No.  1. 
The  contents  of  14  bottles  gave  an  average  or  mean  weight  of 
484.531  grains  each,  or  .678  per  cent,  short  of  the  avoirdupois 
ounce.  From  the  looseness  of  some  of  the  corks,  and  from  having 
noticed  that  8  bottles  in  standing  over  night  with  the  tin  foil 
cover  and  some  of  the  wax  removed,  but  with  the  corks  undis- 
turbed, very  sensibly  lost  weight,  it  is  probable  that  these  bottles 
contained  an  average  avoirdupois  ounce  when  put  up,  and  that  this 
deficiency  is  a  loss  of  water  by  evaporation.  They  are,  therefore, 
assumed  to  have  contained  an  average  of  437.5  grains,  and  this 
is  taken  as  the  basis  of  all  the  calculations. 
The  weather  during  the  first  three  days  of  the  following  obser- 
vations was  clear  and  very  warm.  Afterwards  cooler,  and  gene- 
rally rainy  or  very  damp. 
After  24  hours  exposure  to  ordinary  summer  air,  and  tempera- 
tures from  76°  to  92°,  the  fourteen  ounces  were  found  to  have 
suffered  a  mean  loss  of  45.02  grains  each. 
Exposed  thus  for  nine  consecutive  days  the  lowest  mean  weight 
was  391.18  grains,  and  the  greatest  mean  loss  46.32  grains  each 
or  10.587  per  cent. 
