BORACIC  ACID  SPRINGS  IN  TUSCANY. 
557 
amount  of  sulphurous  gas  evolved  very  possibly  affecting  the 
vegetation  to  a  greater  or  less  extent.  The  boracic  acid  is 
found,  mixed  with  other  matter,  in  three  different  states  : — 
1.  Mixed  with  mud,  forming  a  thick  paste,  almost  solid. 
2.  As  a-  thick,  muddy  solution,  very  much  resembling  Thames 
water  at  low  tide. 
3.  As  a  fountain  of  the  solution,  very  highly  concentrated, 
and  so  pure  that  there  is  not  the  slightest  smell  of  any  compound 
of  sulphur  with  it.  This  is  the  more  remarkable,  as  in  both  the 
other  forms  the  presence  of  sulphur  is  strongly  indicated  by  the 
smell. 
Of  the  pasty  mixture  there  were  only  three  or  four  vats  or 
w^ells  ;  whilst  of  the  more  liquid  preparation  there  were  about 
twelve  or  fourteen, — varying  in  diameter  from  30  to  50  or  60 
feet. 
The  clear  solution  was  thrown  up  to  a  height  of  about  30  feet 
(on  some  days  rather  higher,  and  on  some  not  so  high)  ;  but  to 
prevent  waste,  a  huge  cone-shaped  basket  is  fastened  over  it,  a 
short  distance  above  ground,  by  means  of  which  it  can  be  the 
more,  easily  guided  into  any  one  of  the  numerous  vats  and  coolers 
waiting  to  receive  it. 
The  muddy  liquid  mixture  is  drained  off  into  large  tubs  hold- 
ing about  150  gallons  each.  Upon  cooling,  the  very  impure 
acid  crystallizes  round  the  sides  of  the  tub,  whence  it  is  after- 
wards removed  to  be  purified. 
From  2688  to  3253  casks  of  commercially  pure  boracic  acid 
are  sent  away  from  this  place  yearly,  each  cask  weighing  on  an 
average  300  kilos.  At  a  rough  calculation  this  would  give  us 
1,893,900  kilos,  or  1691  tons,  as  the  quantity  annually  sent  into 
the  market  from  this  one  source.  As  there  are  five  other  sources 
in  various  parts  of  the  mountains,  all  of  them  in  full  action,  and 
two  or  three  much  larger  than  the  one  I  have  seen,  the  sum 
total  would  amount  to,  at  least,  10,500  tons  collected  per  annum. 
I  say  at  least,"  for  I  have  put  the  average  lower  than  it  really 
is,  and  I  have  also  supposed  that  each  spring  gave  the  same 
average  ;  instead  of  which,  two  or  three  of  them,  as  1  have  said 
before,  are  much  larger  than  the  others.  Three  thousand  men 
and  boys  in  all  ai^  employed  in  the  works,  the  men  with  their 
