TIN. 
147 
paration  of  oxygen.  As  to  the  net  cost,  calculated  on  these 
data,  it  is  so  slight  that  it  is  impossible  to  give  the  exact  figure 
or  even  an  approximation  to  it.  In  fact,  we  have  only  to  reckon 
as  cost  the  very  little  coal  required  to  maintain  a  small  appara- 
tus at  red  heat,  and  the  nitrate  of  soda  employed  to  determine 
the  union  of  the  atmospheric  oxygen  with  the  sulphurous  acid  ; 
for  our  process  consists  really  in  taking  oxygen  from  the  air. 
Moreover,  supposing  the  sulphurous  acid  proceeding  from  the 
decomposition  of  sulphuric  acid  to  be  lost,  yet  this  sulphuric 
acid  still  remains  the  most  economical  agent  for  the  production 
of  oxygen,  which  does  not  cost  70  centimes  for  a  cubic  metre 
when  crude  acid  is  used,  and  which  is,  therefore,  in  this  respect, 
for  superior  even  to  binoxide  of  manganese. — Qhem.  News,  Dec. 
1860,  from  Comptes-Rendus, 
TIN. 
If  there  be  any  one  substance  more  than  another  that  has 
rendered  England  famous  throughout  the  world,  it  is  tin.  Cam- 
den, the  historian,  supposes  that  this  country,  from  the  abund- 
ance of  tin  which  it  contains,  was  called  Britain.  In  the  Syriac 
language  varatanae  signifies  land  of  tin;  whence  is  derived 
Britain.  The  mention  of  tin  by  Moses,  in  the  31st  chapter  of 
Numbers,  22d  verse,  is  a  proof  of  its  being  known  from  the  most 
remote  antiquity.  Long  before  the  Christian  era  the  trade  in 
tin  caused  many  a  vessel  to  spread  its  sails  in  the  Mediterra- 
nean Sea,  and  to  cross  the  Bay  of  Biscay  to  fetch  it  from  these 
shores.  The  alchemists  of  old  considered  tin  to  be  a  mixture 
of  silver  and  lead,  but  modern  chemistry  proves  it  to  be  a  dis- 
tinct metal.  About  10,000  tons  of  tin  are  extracted  every  year 
from  the  mines  in  Cornwall  and  Devon,  nearly  the  whole  of 
which  is  consumed  in  the  manufacture  of  tin-plate  {fer-hlanc,  or 
white  iron,  as  the  French  term  it),  that  is,  sheet  iron  coated 
with  tin ;  and  it  is  this  substance  which  constitutes  our  famous 
tin- ware,  which  finds  a  market  from  Naples  to  Japan,  from  New 
York  to  Eupatoria.  Melted  tin  forms  a  sort  of  varnish  for  iron, 
and  prevents  that  metal  from  rusting ;  when  copper  is  coated 
with  it  verdigris  cannot  be  produced.  Tin  and  lead  melted  to- 
gether produce  what  is  called     Britannia  metal of  which  tea- 
