﻿BECKER 
  BROTHERS, 
  

   No. 
  6 
  Murray 
  Street, 
  New 
  York, 
  

  

  -Ltlanufacturers 
  of 
  Balances 
  and 
  Weights 
  of 
  Precision 
  for 
  Chem- 
  

   ists, 
  Assayers, 
  Jewelers, 
  Druggists, 
  and 
  in 
  general 
  for 
  every 
  use 
  

   where 
  accuracy 
  is 
  required. 
  

  

  AMERICAN 
  JOURNAL 
  OF 
  SCIENCE. 
  

  

  Founded 
  by 
  Professor 
  Silliman 
  in 
  1818. 
  

  

  Devoted 
  to 
  Chemistry, 
  Physics, 
  G-eology, 
  Physical 
  Geography, 
  Mineralogy, 
  

   Natural 
  History, 
  Astronomy, 
  and 
  Meteorology. 
  

  

  Editors 
  : 
  James 
  D. 
  Dana 
  and 
  Edward 
  S. 
  Dana. 
  

  

  Associate 
  Editors: 
  J. 
  P. 
  Cooke, 
  Jr., 
  George 
  L. 
  Goodale, 
  and 
  John 
  Trow- 
  

   bridge, 
  of 
  Cambridge, 
  H. 
  A. 
  Newton 
  and 
  A. 
  E. 
  Terrill, 
  of 
  Yale, 
  and 
  G. 
  F. 
  

   Barker, 
  of 
  the 
  University 
  of 
  Pennsylvania, 
  Philadelphia. 
  

  

  Two 
  volumes 
  of 
  480 
  pages 
  each, 
  published 
  annually 
  in 
  MOMHLY 
  XOIBERS. 
  

  

  This 
  Journal 
  ended 
  its 
  first 
  series 
  of 
  50 
  volumes 
  as 
  a 
  quarterly 
  in 
  1845, 
  and 
  its 
  

   second 
  series 
  of 
  50 
  volumes 
  as 
  a 
  two-monthly 
  in 
  1870. 
  The 
  monthly 
  serir~ 
  com- 
  

   menced 
  in 
  1871. 
  

  

  Twenty 
  copies 
  of 
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  original 
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  if 
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   number 
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  desired 
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  on 
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  communicated 
  to 
  tne 
  

   printers 
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   Articles 
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  Notice 
  is 
  always 
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  given 
  when 
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  have 
  been, 
  or 
  are 
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  Subscription 
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  50 
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  ' 
  Ten-volume 
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  The 
  index 
  

   to 
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  xxxi 
  to 
  XL 
  (3d 
  series) 
  was 
  issued 
  in 
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  1891 
  ; 
  price 
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  cents. 
  

  

  Address 
  the 
  Proprietors, 
  

  

  J. 
  D. 
  and 
  E. 
  S. 
  DANA, 
  New 
  Haven, 
  Conn. 
  

  

  

  