﻿LIMESTONES 
  OF 
  NEW 
  YORK 
  AND 
  THEIR 
  ECONOMIC 
  VALUE 
  423 
  

  

  expensive 
  under 
  American 
  conditions. 
  Simpler 
  methods 
  follow- 
  

   ing 
  the 
  recent 
  English 
  or 
  French 
  practice 
  of 
  handling 
  the 
  slurry 
  

   by 
  pumps 
  and 
  drying 
  in 
  flues 
  or 
  on 
  floors 
  of 
  waste 
  heat 
  from 
  the 
  

   kilns 
  would 
  be 
  a 
  much 
  more 
  economical 
  method 
  of 
  dealing 
  with 
  

   wet 
  raw 
  materials. 
  The 
  recent 
  French 
  practice 
  with 
  such 
  ma- 
  

   terials 
  is 
  superior 
  to 
  anything 
  yet 
  suggested 
  for 
  reducing 
  cost 
  of 
  

   labor 
  in 
  handling 
  and 
  drying 
  raw 
  materials 
  which 
  require 
  to 
  be 
  

   balled 
  from 
  slurry 
  before 
  calcination. 
  

  

  A 
  very 
  simple 
  method 
  of 
  preparation 
  of 
  wet 
  raw 
  materials 
  for 
  

   the 
  rotary 
  kiln 
  is 
  now 
  in 
  use 
  in 
  Ohio 
  and 
  Michigan. 
  The 
  raw 
  

   materials 
  there 
  are 
  wet 
  marls 
  and 
  clays 
  and 
  it 
  has 
  been 
  found 
  

   practicable 
  to 
  introduce 
  these 
  materials 
  in 
  a 
  humid 
  or 
  semi- 
  

   humid 
  condition 
  and 
  burn 
  good 
  clinker. 
  At 
  the 
  works 
  at 
  San- 
  

   dusky 
  the 
  material 
  is 
  introduced 
  in 
  a 
  semi-humid 
  condition 
  while 
  

   at 
  Bronson 
  the 
  slurry 
  is 
  introduced 
  into 
  the 
  upper 
  part 
  of 
  the 
  

   kiln 
  by 
  a 
  pump. 
  

  

  With 
  respect 
  to 
  crushing 
  and 
  grinding 
  machinery 
  for 
  hard 
  raw 
  

   materials 
  and 
  for 
  clinker 
  American 
  practice 
  is 
  excellent. 
  

   Crushers 
  of 
  the 
  Blake 
  or 
  Gates 
  type 
  are 
  used 
  for 
  the 
  first 
  re- 
  

   duction, 
  and 
  crackers 
  for 
  J:he 
  coffee-mill 
  type, 
  millstones 
  and 
  im- 
  

   proved 
  mills 
  for 
  the 
  fine 
  grinding. 
  The 
  Griffin 
  mill 
  is 
  an 
  Ameri- 
  

   can 
  invention 
  which 
  has 
  found 
  much 
  favor 
  both 
  here 
  and 
  abroad. 
  

   Its 
  fine 
  grinding 
  is 
  causing 
  it 
  to 
  be 
  favored 
  for 
  raw 
  materials 
  also 
  

   to 
  the 
  neglect 
  of 
  millstones. 
  In 
  the 
  Alpha 
  works 
  of 
  New 
  Jersey, 
  

   the 
  Glens 
  Falls 
  works 
  in 
  New 
  York 
  and 
  in 
  a 
  new 
  plant 
  of 
  the 
  

   American 
  cement 
  co. 
  at 
  Egypt 
  the 
  Griffin 
  mills 
  are 
  used 
  on 
  raw 
  

   materials 
  to 
  the 
  advantage 
  of 
  the 
  product. 
  The 
  German 
  ball-mill, 
  

   in 
  which 
  grinding 
  is 
  effected 
  by 
  the 
  impact 
  and 
  abrasion 
  of 
  steel 
  

   balls 
  rolling 
  freely 
  in 
  a 
  revolving 
  cylinder, 
  has 
  also 
  found 
  favor 
  

   in 
  recent 
  plants. 
  The 
  material 
  enters 
  by 
  a 
  hollow 
  shaft 
  and 
  passes 
  

   out 
  as 
  it 
  is 
  sufficiently 
  reduced 
  to 
  go 
  through 
  screens 
  surround- 
  

   ing 
  the 
  cylinders. 
  The 
  ball-mill 
  has 
  been 
  employed 
  on 
  clinker 
  for 
  

   first 
  reduction 
  only 
  in 
  conjunction 
  with 
  Danish 
  tube 
  mills 
  to 
  do 
  

   the 
  finer 
  grinding. 
  In 
  it 
  the 
  grinding 
  is 
  done 
  by 
  the 
  impact 
  of 
  

   flint 
  balls 
  and 
  with 
  a 
  moderate 
  feed 
  very 
  fine 
  grinding 
  can 
  be 
  

  

  