THE  PROVINCES  AND  THE  TREATY  PORTS  267
Argentiferous  lead  ranks  next  in  importance,  of  which  over
twenty  mines  were  known.  Tin  comes  from  Kochiu,  about
20  miles  from  Mengtsz,  from  which  port  4&gt;5 00  tons
were  exported  in  1905*  Coal,  though  known  to  exist,  has
not  been  mined  to  any  considerable  extent.  The  salt
produced  in  the  province  supplies  its  own  population.
Along  the  southern  and  western  frontier  of  the  province  are
three  treaty  ports.
Mengtsz  (23 0  24'  N.,  103 0  22'E.),  population  12,000,  may
be  taken  to  illustrate  the  frontier  port,  and  is  the  only  one
of  the  four  now  open  which  has  developed  a  trade  worthy
of  consideration.  Situated  at  an  altitude  of  4,500  feet,  it
is  40  miles  distant  from  its  junk  port,  Manhao  (altitude
900  feet)  on  the  Red  River,  which  again  is  six  days’  junk
journey  above  Hokow  ;  this  last  place  on  the  Yunnan  side,
opposite  to  Laokay  on  the  Tonkin  side  of  the  frontier,  was
in  1895  made  the  first  sub-port  of  entry  for  the  Mengtsz
district.  Before  the  building  of  railways,  the  course  for
imports  from  Haiphong  during  the  summer  floods  was  by
steamer  to  Laokay,  and  during  the  winter  by  steamer  to
Yenbay,  thence  by  native  craft  up  the  rapids  to  Laokay  ;
thence  by  native  craft  to  Manhao  ;  thence  by  pack-animal
to  Mengtsz,  and  so  on  for  distribution  through  the
province,  each  pack-animal  taking  an  average  load  of
160  lbs.  Mengtsz  was  opened  as  a  treaty  port  in
1889,  with  the  special  stipulation,  not  applying  to  coast
and  riverine  ports,  that  imports  should  pay  only  seventenths
  and  exports  only  six-tenths  of  the  tariff  duty  ;
moreover,  when  the  revised  Import  Tariff  was  put  in
force  in  1902,  it  was  held  that  the  old  tariff,  with  its
lower  duties,  was  still  to  be  applied  to  the  frontier
ports.  Transit  dues,  being  half  the  tariff  duty,  are,  however,
based  on  the  undiminished  rate,  and  it  is  chiefly  to  avoid
the  Chinese  inland  taxation  that  the  trade  of  Mengtsz,  in
particular,  has  been  developed  ;  of  the  imports  in  1904
nearly  74  per  cent,  continued  their  journey  under  transit
pass,  one-sixth  of  this  transit  trade  adopting  this  roundabout ­
  way  for  Kweichow.  The  opening  of  Wuchow  (1897)