492  Laboratory  Notes.  j^ig8* 
was  found  to  give  very  little  color,  either  with  sulphuric  acid  at  ioo°C. 
or  with  Husemann's  test. 
It  is  perhaps  worthy  of  mention  that  brucia,  with  concentrated  sul- 
phuric acid,  even  in  the  cold,  gives  a  light  red  color.  This  fact  (stated 
in  the  books)  must  be  borne  in  mind  in  testing  for  nitric  acid  by  brucia. 
The  color  was  obtained  alike  with  each  sample  of  purified  sulphuric 
acid  used  in  this  work  with  Husemann's  test,  the  tests  being  made  to 
settle  a  doubt  whether  the  reaction  given  for  sulphuric  acid  with  brucia 
could  be  due  at  all  to  any  trace  of  nitric  acid.  The  color  of  brucia 
with  sulphuric  acid,  on  warming  and  treating  with  stannous  chloride 
solution,  undergoes  no  other  change  than  a  gradual  fading  toward  the 
yellow,  but  in  presence  of  nitric  acid  (as  is  well  known)  the  stannous 
chloride  developes  an  intense  purple. 
I  am  indebted  to  Mr.  H.  S.  Wyman  for  performing  most  of  the 
operations  stated  in  this  note. 
XI.    Microscopic  Examination  of  Ground  Coffee   and  Coffee 
Extract. 
The  samples  were  gathered  indiscriminately  from  the  grocer  trade  of 
New  York  City  and  Ann  Arbor,  Mich.,  and  subjected  to  microsco- 
pical and  chemical  examination  by  Miss  M.  E.  Johnson. 
•Ground  Coffe  contained —  Coffee  Essence  contained — 
No.  1,  coffee,  chicory,  wheat.  No.  i,  licorice  root,  wheat,  beans. 
2,  coffee,  chicory.  2,  chicory. 
3,  coffee,  chicory,  wheat,  beans.  3,  coffee,  chicory. 
4,  coffee,  chicory.  4,  chicoiy,  burnt  sugar. 
5,  coffee,  chicory,  wheat,  beans  5,  coffee,  chicory. 
6,  coffee,  chicory. 
The  manufacture  of  coffee  extract  suggests  the  question  whether  it 
may  be  made  from  unground  coffee,  with  sale  of  the  partly  exhausted 
coffee  berry.  The  exhaustion  of  unground  cinnamon  bark  is  well 
known,  unbroken  cinchona  bark  has  been  reported  deprived  of  quinia 
and  charged  with  chinoidin  instead,  and  analysts  are  alert  for  finding 
spent  tea.  Hager  states  that  roasted  coffee  contains  at  the  most  20  per 
cent,  of  soluble  matter  ("  Untersuchungen,"  II,  613).  Wanklyn 
quotes  Vogel's  report  of  39  per  cent,  of  soluble  solids  in  roasted  coffee, 
with  the  remark  that  it  appears  rather  high.  Hassal  reports  finding 
the  extract  of  six  samples,  with  an  average  of  28  per  cent,  and  ranging 
from  23  to  30.    In  a  single  instance,  that  of  a  coffee  purchased  as 
