﻿544 
  

  

  Incidentally 
  he 
  was 
  of 
  opinion 
  that 
  the 
  so-called 
  Piper 
  1:1:4 
  

   formula, 
  that 
  is 
  to 
  say, 
  the 
  proportion 
  of 
  1 
  lb. 
  of 
  lime 
  and 
  1 
  lb. 
  of 
  

   sulphur 
  to 
  4 
  gals, 
  water, 
  costs 
  from 
  one-half 
  to 
  two-thirds 
  less 
  per 
  gallon 
  

   than 
  do 
  the 
  washes 
  prepared 
  by 
  other 
  formulae 
  in 
  common 
  use, 
  and 
  

   that 
  the 
  cost 
  of 
  the 
  efficient 
  sulphur 
  in 
  solution 
  is 
  also 
  less 
  in 
  about 
  

   the 
  same 
  proportion. 
  The 
  Piper 
  formula 
  contains 
  lime 
  in 
  excess 
  of 
  

   the 
  amount 
  required 
  to 
  combine 
  with 
  the 
  sulphur 
  used, 
  but 
  this 
  hme 
  

   is 
  present 
  in 
  the 
  wash 
  as 
  " 
  whitewash," 
  and 
  serves 
  to 
  render 
  the 
  spray 
  

   visible 
  on 
  trees 
  and 
  so 
  aid 
  in 
  thoroughness 
  of 
  application. 
  

  

  The 
  author 
  points 
  out 
  that 
  it 
  is 
  by 
  no 
  means 
  an 
  easy 
  matter 
  to 
  

   determine 
  with 
  anything 
  like 
  accuracy 
  the 
  chemical 
  constitution 
  of 
  

   a 
  hme-sulphur 
  spray, 
  and 
  as 
  this 
  has 
  been 
  accomplished 
  by 
  himself 
  

   and 
  his 
  colleague 
  at 
  the 
  cost 
  of 
  a 
  large 
  amount 
  of 
  labour, 
  he 
  deals 
  with 
  

   it 
  in 
  detail 
  and 
  discusses 
  at 
  considerable 
  length 
  the 
  very 
  important 
  

   question 
  of 
  the 
  nature 
  of 
  the 
  calcium 
  polysulphide 
  produced, 
  and 
  also 
  

   the 
  effects 
  of 
  the 
  time 
  of 
  boihng 
  upon 
  the 
  amount 
  produced, 
  as 
  well 
  

   as 
  on 
  its 
  composition. 
  He 
  further 
  discusses 
  the 
  effect 
  of 
  the 
  carbon 
  

   dioxide 
  of 
  the 
  atmosphere 
  in 
  decomposing 
  the 
  diluted 
  solution 
  when 
  

   sprayed 
  upon 
  the 
  tree, 
  and 
  found 
  that 
  when 
  pure 
  CO^ 
  was 
  passed 
  

   through 
  the 
  solution 
  a 
  large 
  quantity 
  of 
  sulphuretted 
  hydrogen 
  (H.S), 
  

   apparently 
  as 
  much 
  as 
  if 
  some 
  strong 
  acid 
  was 
  used, 
  was 
  developed. 
  

   Further 
  experiments 
  were 
  made 
  by 
  passing 
  air 
  through 
  the 
  diluted 
  

   lime-sulphur, 
  and 
  although 
  the 
  quantity 
  of 
  sulphur 
  precipitated 
  and 
  

   the 
  quantity 
  of 
  H.^S 
  given 
  off 
  was 
  relatively 
  small, 
  there 
  is 
  no 
  doubt 
  

   that 
  something 
  of 
  this 
  kind 
  must 
  be 
  reckoned 
  with 
  in 
  the 
  practical 
  

   use 
  of 
  the 
  spray. 
  

  

  The 
  author 
  discusses 
  in 
  detail 
  the 
  reaction 
  which 
  takes 
  place 
  between 
  

   sulphur 
  and 
  calcium 
  hydroxide 
  in 
  aqueous 
  solution, 
  and 
  quotes 
  the 
  

   experiments 
  of 
  other 
  workers 
  who 
  have 
  investigated 
  this 
  matter. 
  

   He 
  then 
  deals 
  with 
  the 
  difficulties 
  of 
  determining 
  separately 
  the 
  

   various 
  products 
  formed, 
  namely, 
  calcium 
  pentasulphide, 
  tetra- 
  

   sulphide, 
  thiosulphate, 
  and 
  sulphite. 
  All 
  these 
  compounds 
  are 
  readily 
  

   soluble 
  in 
  water, 
  with 
  the 
  exception 
  of 
  the 
  sulphite, 
  which 
  is 
  relatively 
  

   insoluble. 
  The 
  average 
  of 
  seven 
  lots 
  of 
  solution 
  prepared 
  gave 
  the 
  

   following 
  results 
  per 
  100 
  cc. 
  : 
  — 
  Specific 
  gravity, 
  1*287 
  ; 
  lime 
  compound 
  

   as 
  polysulphide, 
  11*29 
  ; 
  as 
  thiosulphate, 
  1*13 
  ; 
  as 
  insoluble 
  sulphite 
  

   (estimated), 
  4*51 
  ; 
  sulphur 
  as 
  polysulphide, 
  30*67 
  ; 
  sulphur 
  as 
  thio- 
  

   sulphate, 
  1*29 
  ; 
  sulphur 
  as 
  insoluble 
  sulphite, 
  2*56. 
  In 
  the 
  seven 
  

   specimens 
  analysed 
  the 
  ratio 
  of 
  lime 
  (CaO) 
  to 
  sulphur 
  required 
  was 
  

   1:2, 
  and 
  the 
  author 
  thinks 
  he 
  is 
  justified 
  in 
  saying 
  that 
  this 
  is 
  the 
  

   proportion 
  of 
  lime 
  to 
  sulphur 
  which 
  reacts 
  in 
  the 
  preparation 
  of 
  the 
  

   more 
  concentrated 
  commercial 
  hme-sulphur 
  solution. 
  He 
  regrets 
  that 
  

   he 
  had 
  no 
  opportunity 
  of 
  examining 
  more 
  diluted 
  solutions 
  prepared 
  

   under 
  commercial 
  conditions, 
  but 
  quotes 
  Thatcher 
  and 
  Van 
  Slyke 
  

   to 
  the 
  effect 
  that 
  the 
  ratio 
  of 
  lime 
  to 
  sulphur 
  would, 
  in 
  this 
  case, 
  be 
  

   somewhat 
  greater 
  than 
  1:2, 
  and 
  that 
  in 
  some 
  cases 
  it 
  might 
  perhaps 
  

   be 
  as 
  high 
  as 
  1 
  : 
  1*25 
  ; 
  he 
  says 
  that 
  this 
  theoretical 
  basis 
  will 
  not 
  apply 
  

   exactly 
  to 
  the 
  preparation 
  of 
  small 
  amounts 
  of 
  solution, 
  say 
  150 
  gallons 
  

   or 
  less, 
  where 
  oxidation 
  of 
  the 
  polysulphides 
  occurs 
  to 
  a 
  considerable 
  

   extent 
  through 
  contact 
  with 
  air. 
  

  

  The 
  author 
  then 
  proceeds 
  to 
  discuss 
  the 
  valuation 
  of 
  hme-sulphur 
  

   as 
  an 
  insecticide. 
  He 
  says 
  that 
  in 
  many 
  cases 
  the 
  total 
  lime 
  contained, 
  

   the 
  total 
  sulphur 
  contained, 
  and 
  the 
  specific 
  gravity 
  only 
  are 
  ascer- 
  

  

  