182 
VARIETIES. 
wild  in  the  distant  stations  on  the  extra- Chilian  Alps  where  it  has  hitherto 
been  thought  so.  When  we  consider  that  on  the  arid  Cordilleras  the  In- 
dians often  fix  their  patches  of  cultivation  on  points  that  would  appear 
almost  inaccessible  to  our  European  farmers,  it  is  easy  to  imagine  how  a 
traveller  visiting  one  of  these  stations  which  had  been  long  abandoned,  and 
finding  the  potato  accidentally  surviving,  would  conclude  that  it  must  be 
really  wild  there.  But  where  is  the  proof?  For  my  own  part,  after 
reading  all  that  has  been  written  on  the  subject,  I  am  forced  to  conclude 
that  its  real  native  country  is  Chili  rather  than  Peru.  There  can  be  no 
doubt  that  the  cultivation  of  the  potato  is  of  great  antiquity,  seeing  that 
at  the  time  of  the  conquest  it  was  found  in  every  part  of  the  temperate 
portions  of  Western  America  from  Chili  to  New  Grenada  and  even  Mexico, 
and  I  am  very  much  inclined  to  think  that  it  was  everywhere  the  same 
species  ;  for  although  the  potato  grown  on  the  high  plains  of  Peru  posses- 
ses some  degree  of  acridity,  and  resists  frost  better  than  those  with  which 
we  are  familiar,  it  does  not  appear  from  its  botanical  characters  that  it  can 
be  distinguished  as  a  species  rather  than  a  simple  race.  D'Orbigny 
brought  from  the  summit  of  the  Cerro  de  Potosi,  and  consequently  from  an 
elevation  of  14,640  feet,  a  form  of  the  potato  which  might  be  called  Alpine. 
The  leaves  grow  in  rosettes  and  the  flowers  sit  perfectly  close  upon  the 
root.  I  found  the  same  form  in  a  piece  of  ancient  cultivated  ground  on 
the  Peruvian  plateau  at  the  height  of  12,000  feet." — Lon.  Pharm.  Jour., 
Bee.  1859, 
Metallic  Cement. — M.  Greshiem  states  that  an  alloy  of  copper  and  mer- 
cury, prepared  as  follows,  is  capable  of  attaching  itself  firmly  to  the  sur- 
faces of  metal,  glass,  and  porcelain.  From  20  to  30  parts  of  finely  divided 
copper,  obtained  by  the  reduction  of  oxide  of  copper  with  hydrogen,  or  by 
precipitation  from  solution  of  its  sulphate  with  zinc,  are  made  into  a  paste 
with  oil  of  vitriol  and  70  parts  of  mercury  added,  the  whole  being  well  tri- 
turated. When  the  amalgamation  is  complete,  the  acid  is  removed  by 
washing  with  boiling  water,  and  the  compound  allowed  to  cool.  In  ten  or 
twelve  hours  it  becomes  sufficiently  hard  to  receive  a  brilliant  polish,  and 
to  scratch  the  surface  of  tin  or  gold.  By  heat  it  assumes  the  consistence 
of  wax,  and,  as  it  does  not  contract  on  cooling,  M.  Greshiem  recommends 
its  use  by  dentists  for  stopping  teeth. — Ibid. 
Cleaning  Glasses  and  Capsules. — There  is  often  a  difficulty  in  cleaning 
glasses  or  porcelain  capsules  to  which  organic  matters  have  adhered,  and 
in  course  of  time  become  so  hard  and  dry  that  they  resist  all  solvents. 
The  following  process  will  be  found  to  answer  in  almost  every  case  : — 
The  spots  to  be  cleaned  are  moistened  with  concentrated  sulphuric  acid, 
and  powdered  bichromate  of  potash  is  sprinkled  upon  the  acid ;  the  objects 
are  then  left  standing  for  some  hours  (through  the  night)  in  a  moderately 
