LIME    INDUSTRY    OF    KNOX    COUNTY,    ME. 
395 
unburned  for  use  in  pulp  mills  or  as  flux, a  and  some  is  used  in  the  production  of  a  hydrated 
lime,  to  be  discussed  later  more  fully.  The  rock  is  not  suitable  for  building  purposes.  The 
production  in  this  region  of  common  lime,  hydrated  lime,  and  limestone  for  pulp  and  flux 
purposes  since  the  year  1898  is  given  in  the  following  table: 
Production  of  lime,  etc.,  in  Knox  County. b 
Year. 
Common 
lime. 
Hydrated. 
Lime  for 
pulp- 
making 
purposes 
(mainly 
magne- 
sian) .  c 
Limestone 
for  flux 
and  pulp- 
making 
purposes. 
1898         
Casks.d 
1,610,178 
1,939,427 
1,728,134 
1,962,717 
1,589,982 
1 ,  81 7,  787 
1.792,559 
Tons. 
Casks.d 
if) 
if) 
if) 
94, 133 
78,157 
72,001 
52,909 
Casks,  e 
if) 
if) 
if) 
if) 
if) 
if) 
21  000 
1899 
1900        
1901 
1902 
1903 
10,000 
12,500 
1904 
b  Compiled  from  records  of  lime  inspectors  at  the  various  ports  and  from  the  records  of  private 
companies. 
cAll  from  quarries  at  West  Warren. 
d  Of  200  pounds. 
e  Of  400  pounds. 
/  Statistics  rot  available. 
About  two-thirds  of  the  common  lime  produced  goes  to  the  New  York  market,  where  for 
many  years  it  has  had  the  highest  reputation.  Nearly  all  of  this  is  shipped  by  water,  the 
largest  of  the  companies  maintaining  a  fleet  of  six  barges,  each  capable  of  carrying  15,000 
casks  (200  pounds  each)  of  lime  and  of  bringing  on  the  return  voyage  1,500  tons  of  coal. 
The  remainder  of  the  product  goes  to  Boston  and  other  New  England  markets.  In  spite 
of  the  fact  that  freight  rates  are  lower  by  rail,  most  of  the  lime  shipped  to  Boston  goes  by 
water,  as  the  Boston  building  contractors  have  good  docking  facilities  but  in  few  cases 
have  railroad  yards.  For  the  rest  of  New  England  the  shipments  are  usually  by  rail.  From 
one-fourth  to  one-third  of  the  lime  is  of  finishing  grade. 
Of  recent  years  a  process  has  been  taken  up  by  the  Rockland-Rockport  Lime  Company 
which  has  not  only  proved  a  great  success  here  and  elsewhere,  but  which  seems  to  point 
out  an  important  line  of  future  development  in  the  lime  industry.  This  process  consists  in 
a  complete  hydration  of  the  lime  before  it  is  placed  on  the  market.  It  has  been  carried  on 
successfully  in  other  parts  of  the  country  under  a  variety  of  patents,  the  product  being 
variously  known  as  "new-process  lime,"  " hydrated  lime,"  "limoid,"  etc.  The  Rockland 
product  goes  under  the  name  of  " prepared  pure  white  lime."  While  differing  in  details, 
the  various  processes  are  identical  in  principle.  The  lime  after  burning  is  crushed  or  ground 
until  no  lumps  larger  than  1  inch  in  size  remain.  It  is  then  transferred  to  a  mixer,  where 
it  is  thoroughly  mixed  with  about  25  per  cent  of  its  weight  of  water,  the  chemical  change 
produced  being  represented  by  the  equation — 
CaO+H20=Ca  (OH)s 
Lime+ water =lime  hydrate. 
A  description  of  the  effects  produced  by  this  hydration  and  of  the  subsequent  steps  in  the 
process  of  manufacture  may  be  quoted  from  one  of  the  prospectuses  of  the  Rockland-Rock- 
port Lime  Company.  The  lime  "undergoes  a  radical  change,  its  heating  and  expanding 
qualities  being  entirely  removed;  it  is  then  conveyed  to  bins  where  it  is  allowed  to  age.  the 
same  result  being  obtained  as  when  slaking  lime  several  months  before  it  is  used;  it  is  then 
bolted  to  the  varying  degrees  of  fineness  according  to  the  different  purposes  for  which  it  is 
a  Only  a  very  small  amount  is  used  for  flux. 
