350 
SILVERING  UPON  GLASS. 
be  made  at  the  point  at  which  the  cooling  fluid  will  sustain  the 
myroxylon  upon  its  surface,  dropping  it  upon  the  centre,  and 
stirring  slowly  at  first  with  the  point  of  the  wood  spatula,  grad- 
ually incorporating  it  with  the  mass. 
Where  this  care  is  not  observed  the  mass  is  disfigured  with 
minute  dark  specks  ;  and  should  the  addition  be  made  before 
the  point  in  cooling  mentioned  is  reached,  a  separation  of  con- 
stituents is  effected,  and  collects  as  a  resinous  globule  in  the 
bottom  of  the  vessel,  and  cannot  afterwards  be  properly  incor- 
porated. 
The  process  was  applied  to  most  preparations,  officinal  and 
otherwise,  which  in  the  course  of  business  would  suggest  its  use, 
since  November,  1865,  among  which  were  the  following : 
Unguentum  adipis, 
"       Aquse  rosae, 
"  Gallse, 
"  Hydrargyri, 
"        Hydrarg,  oxid.  rub., 
"  "  nitrat., 
"        Plumbi  carb., 
"        Zinci  oxidi, 
Cerat.  plumbi  subacet., 
"  Adipis, 
"  Cetacei, 
"    Zinci  carbonatis. 
They  were  dispensed  at  varying  intervals,  kept  indefinitely 
well,  and,  upon  inquiry  instituted  as  to  their  behavior  thera- 
peutically, confirmed  the  supposition  of  their  properties  being 
unaltered  by  the  combination. — Report  of  the  Alumni  Assoc. 
of  the  Phila.  Col.  of  Pharm.,  1867. 
Germantown,  Pa. 
SILVERING  UPON  GLASS. 
Having  occasion  recently  to  silver  some  thin  microscopic  glass, 
several  processes  were  tried  with  indifferent  success,  until  finally 
I  hit  upon  Bothe's  method  as  modified  by  Bottger  (J.  pr.  Ch., 
xcii,  494)  which  afforded  most  excellent  results.    Its  simplicity, 
