weed.]  HOT    SPRINGS    AND    HOT-SPRING    DEPOSITS.  599 
heat  and  the  constancy  of  supply  day  and  night  for  domestic  uses  are 
of  great  value  to  the  consumer. 
At  various  other  points  the  waters  are  used  for  heating  the  hotels 
and  cottages  built  about  hot  springs,  as,  for  example,  at  Boulder  Hot 
Springs,  Mont. 
At  Gregson  Springs,  Mont.,  the  waters  are  used  to  heat  green- 
houses. Perhaps  the  most  striking  example  of  this  is  seen  at  the 
Upper  Geyser  basin,  Yellowstone  Park,  where  the  ingenious  keeper 
of  the  hotel  supplied  himself  throughout  the  winter,  and  the  guests 
in  summer,  with  fresh  vegetables  grown  in  a  greenhouse  erected  over 
a  small  spring  of  boiling  water.  The  exuberant  growth  of  the  plants 
in  this  house  proved  a  marvel  to  all  visitors. 
HOT  SPRING  DEPOSITS. 
The  waters  of  hot  springs,  particularly  those  of  high  tempera- 
ture, invariably  carry  more  or  less  mineral  matter  in  solution.  While 
the  soluble  salts,  such  as  sodium  sulphate,  are  carried  off  by  the  waters, 
frequently  an  incrustation  is  formed  in  the  fissure  or  tube  from 
which  the  waters  issue,  or  on  the  surface  about  the  spring  where  the 
water  overflows.  The  most  common  deposit  is  travertine,  or  calc- 
sinter,  or  calc-tufa  (carbonate  of  lime)  ;  less  commonly  it  is  sili- 
ceous sinter,  also  known  as  geyserite.  If  the  hot-spring  fissure  is 
coated  or  filled  by  similar  material,  veins  are  formed,  which  are  in 
numerous  eases  known  to  be  slightly  metalliferous. 
Though  the  formation  of  ore  deposits  by  the  agency  of  hot  springs 
is  well  recognized  by  mining  men,  examples  of  such  deposits  now 
actually  forming  are  comparatively  rare.  The  Sulphur  Bank,  Cali- 
fornia, cinnabar  deposits  and  Steamboat  Springs,  Nevada,  are  two 
noted  localities  in  the  United  States.  The  deposits  of  Boulder  Hot 
Springs  and  Anaconda  Hot  Springs,  Montana,  arc  of  scientific  inter- 
est, though  the  precious-metal  content  is  minute.  An  interesting 
example  occurs  in  Java,  where  the  hot  springs  of  Gunung  Kendeng 
district  contain  iodide  of  copper,  from  the  waters  of  which* copper  is 
obtained  by  evaporation,  the  product  being  5,161  pounds  in  1899.° 
Tin-bearing  sinters,  formed  b}^  hot  springs,  are  worked  in  the  Malay 
Peninsula,  and  the  hot  waters  of  several  Japanese  mines  are  known 
to  contain  considerable  amounts  of  various  metals. 
The  Steamboat  Springs,  Nevada,  have  recently  attracted  renewed 
attention  because  of  the  discovery  that  the  alluvial  gravels  underly- 
ing the  hot  spring  sinters  are  encrusted  and  cemented  by  stibnite  and 
pyrite,  the  antimony  ore  being  in  considerable  abundance.  It  has 
recently  been  described  by  Lindgren.6 
"  Stevens  Copper  Handbuch,  vol.  4,  1904,  p.  150. 
'■Uull.   Am.    Inst.   Min.   Eng.,   Mar.,    1905,   p.   27."). 
