BORAX  IN  CALIFORNIA. 
237 
and  were,  in  1864,  preparing  to  manufacture  borax  on  a  large 
scale. 
The  water  collected  from  the  Borax  Lake  in  September,  1863, 
as  analyzed  by  G.  E.  Moore,  contained  2401*56  grains  of  solid 
matter  to  the  gallon,  of  which  about  one-half  was  common  salt, 
one  quarter  carbonate  of  soda,  and  the  remainder  chiefly 
borate  of  soda,  there  being  281*48  grains  of  the  anhydrous 
biborate,  equal  to  535*08  of  crystallized  borax  to  the  gallon. 
Traces  of  iodides  and  bromides  were  also  detected.  A  sample 
of  water  taken  from  the  interior  of  a  coffer-dam  sunk  in 
the  middle  of  the  lake,  and  which  had  been  allowed  to  fill  by 
percolation  from  the  bottom  upward,  was  found  to  be  more  con- 
centrated, yielding  3573*46  grains  of  solid  matter  to  the  gallon ; 
but  it  contained  nearly  the  same  ingredients,  and  in  the  same 
proportions,  as  the  water  of  the  lake  itself.  The  borax,  being 
the  least  soluble  substance  contained  in  any  notable  quantity  in 
the  water,  has  in  process  of  time  crystallized  out  to  a  consider- 
able extent,  and  now  exists  in  the  bottom  of  the  lake  in  the  form 
of  distinct  crystals,  which  are  of  all  sizes,  from  microscopic 
dimensions  up  to  two  or  three  inches  across.  These  crystals 
form  a  layer  immediately  under  the  water,  intermixed  with  blue 
mud  of  varying  thickness ;  as  observed  in  the  coffer-dam  sunk 
in  1863,  the  layer  of  crystals  was  about  eighteen  inches  thick, 
and  beneath  it  was  mud  without  crystals.  The  thickness,  how- 
ever, of  the  deposit  is  undoubtedly  very  variable,  and  there  are, 
in  places,  several  layers  of  them  separated  by  beds  of  clay  or 
mud.  It  is  believed,  by  those  who  have  examined  the  bottom  of 
the  lake,  that  several  million  pounds  of  borax  may  be  obtained 
from  it  by  means  of  movable  coffer-dams,  at  a  moderate  expense, 
and  so  as  to  yield  a  handsome  profit  to  those  engaged  in  the 
enterprize.  How  much  of  a  supply  of  water  could  be  obtained 
by  boring,  and  what  its  quality  would  be,  can  hardly  be  settled 
in  any  other  way  than  by  actual  experiment. 
Lying  about  a  mile  beyond  the  ridge  which  borders  the  Borax 
Lake  on  the  north-east,  and  at  the  foot  of  a  shorter  arm  of 
Clear  Lake,  which  extends  off  to  the  south-east  parallel  with  the 
longer  one,  is  an  interesting  locality  where  solfatara  action  is 
still  going  on,  and  where  a  large  amount  of  sulphur  has  accu- 
