208 
PROCESS  FOR  TINNING  METALS. 
pressed  between  folds  of  blotting-paper,  and  were  then  repeatedly 
crystallized  out  of  spirit  of  wine.  The  crystals  purified  in  this 
way  were  of  a  considerable  size,  being  about  a  quarter  of  an 
inch  in  length  and  nearly  colorless.  Their  form  was  that  of 
oblique,  four-sided  prisms,  precisely  similar  to  piperine.  They 
are  very  soluble  in  hot  spirit  of  wine,  pretty  soluble  in  ether, 
but  insoluble  in  water.  When  distilled  with  caustic  potash  they 
yield  a  volatile  base,  which  has  the  characteristic  odor  of 
piperidine. 
The  subjoined  analysis  of  these  crystals  demonstrates  that 
they  are  identical  with  piperine  : — 
I.  0.2160  grms.  gave  0.5690  grms.  of  C02  and  0.1285  HO. 
II.  0.2325  grms.  gave  0.6105  grms.  of  C02  and  0.1405  HO. 
III.  0.5235  grms.  burnt  with  soda-lime,  gave  0.1755  platinum. 
CALCULATED. 
ANALYSIS. 
Regnault. 
Gerhardt. 
Laurent. 
Stenhouse. 
C68  -  -  71.58 
H3S--  6.67 
N2  -  -  4.91 
012--  16.84 
71.04  -  -71.34 
6.72  -  -  6.84 
4.94  -  -  — 
71.52 
6.66 
4.82 
71.66 
6.66 
71.84  --71.61 
6.61  --  6.71 
4.76  -  -  — 
It  appears,  therefore,  that  whatever  may  be  the  botanical 
characters  of  African  cubebs  their  chemical  properties  indicate 
that  they  are  really  a  species  of  pepper,  containing  as  they  do 
piperin  and  not  cubebin,  the  non-nitrogenous  crystallizable  prin- 
ciple of  the  cubeb  tribe,  which  possesses  no  basic  properties. — 
London  Pharm.  Jour.  Feb.  1855. 
PROCESS  FOR  TINNING  METALS. 
By  MM.  Roseleur  and  Boucher. 
The  authors  tin  metals  by  decomposing  solutions  of  certain 
double  salts  of  tin,  especially  the  phosphate,  pyrophosphate,  bo- 
rate and  sulphite,  by  means  of  the  galvanic  current.  A  solu- 
tion for  this  purpose  is  obtained  by  dissolving  3  kilogrms.  of 
pyrophosphate  of  potash  and  500  grms.  of  protochloride  of  tin, 
in  200  litres  of  water.  The  temperature  is  raised  to  about  186°  F., 
