﻿82 
  Scientific 
  hitelligence. 
  

  

  minute 
  description 
  of 
  the 
  quarries 
  and 
  stone 
  industry 
  of 
  the 
  king- 
  

   dom 
  of 
  Saxony. 
  

  

  The 
  volume 
  should 
  answer 
  the 
  same 
  purpose 
  in 
  Germany 
  that 
  

   the 
  admirable 
  hand-books 
  of 
  Merrill 
  have 
  done 
  in 
  this 
  country. 
  

  

  L. 
  V. 
  p. 
  

  

  10. 
  Studies 
  in 
  the 
  Amijhiholes 
  and 
  Pyroxenes. 
  — 
  Attention 
  must 
  

   be 
  called 
  to 
  two 
  important 
  articles 
  published 
  by 
  R. 
  A. 
  Daly 
  in 
  the 
  

   Proceedings 
  of 
  the 
  American 
  Academy, 
  volume 
  xxxiv. 
  The 
  first 
  

   (pp. 
  311-323) 
  gives 
  a 
  minute 
  discussion, 
  with 
  several 
  plates, 
  of 
  the 
  

   optical 
  characters 
  in 
  the 
  vertical 
  zone 
  of 
  amphiboles 
  and 
  pyrox- 
  

   enes, 
  showing 
  with 
  this 
  a 
  new 
  method 
  of 
  determining 
  the 
  ex- 
  

   tinction-angles 
  from 
  cleavage 
  plates. 
  

  

  The 
  second, 
  a 
  larger 
  paper 
  (pp. 
  373-429, 
  pi. 
  i-iv), 
  takes 
  up 
  the 
  

   subject 
  of 
  the 
  etching 
  figures 
  of 
  these 
  minerals, 
  particularly 
  those 
  

   of 
  the 
  amphibole 
  group. 
  The 
  care 
  with 
  which 
  the 
  author 
  has 
  

   worked 
  out 
  the 
  special 
  conditions 
  necessary 
  to 
  obtain 
  the 
  best 
  

   results 
  and 
  the 
  fullness 
  with 
  wtich 
  he 
  describes 
  his 
  experiments, 
  

   make 
  his 
  paper 
  of 
  great 
  value 
  to 
  all 
  interested 
  in 
  this 
  subject, 
  

   aside 
  from 
  the 
  conclusions 
  which 
  he 
  has 
  deduced. 
  Among 
  other 
  

   points 
  he 
  proves 
  that 
  the 
  amphiboles 
  are 
  throughout 
  holohedral. 
  

   He 
  also 
  shows 
  that 
  this 
  method 
  of 
  investigation 
  serves 
  to 
  exhibit 
  

   the 
  close 
  relationship 
  existing 
  between 
  the 
  different 
  members 
  Of 
  

   the 
  group, 
  as 
  too 
  between 
  them 
  and 
  the 
  corresponding 
  pyroxenes. 
  

   Further, 
  it 
  emphasizes 
  the 
  distinction 
  between 
  the 
  non-aluminous 
  

   and 
  aluminous 
  amphiboles, 
  usually 
  insisted 
  upon 
  in 
  works 
  on 
  

   mineralogy, 
  and 
  at 
  the 
  same 
  time 
  shows 
  the 
  great 
  importance 
  of 
  

   a 
  sesquioxide, 
  whether 
  ferric 
  oxide 
  or 
  alumina. 
  In 
  regard 
  to 
  

   certain 
  members 
  of 
  the 
  amphibole 
  group, 
  the 
  following 
  conclu- 
  

   sions 
  are 
  given 
  : 
  

  

  '* 
  Glaucophane 
  and 
  gastaldite 
  are 
  the 
  same 
  species, 
  and 
  both 
  

   isomorphous 
  with 
  hornblende. 
  Arfvedsonite 
  appears 
  to 
  hold 
  a 
  

   more 
  or 
  less 
  independent 
  place 
  in 
  the 
  family 
  of 
  amphiboles. 
  

   Barkevikite 
  is 
  more 
  closely 
  related 
  to 
  common 
  hornblende 
  than 
  

   to 
  arfvedsonite. 
  Anthophyllite 
  and 
  gedrite 
  are 
  plainly 
  ortho- 
  

   rhombic 
  and 
  holohedral. 
  Aenigmatite 
  diverges 
  considerably 
  from 
  

   the 
  amphibole 
  habit, 
  but 
  betrays 
  a 
  tendency 
  toward 
  symmetrical 
  

   cohesional 
  propert}^, 
  as 
  it 
  does 
  toward 
  crystallographic 
  symme- 
  

   try." 
  Incidentally 
  the 
  author 
  has 
  found 
  an 
  amphibole 
  so 
  peculiar 
  

   in 
  etching 
  figures 
  that 
  he 
  has 
  separated 
  it 
  as 
  a 
  special 
  variety 
  

   under 
  the 
  name 
  philipstadite. 
  (See 
  p. 
  83.) 
  

  

  11. 
  Brief 
  Notices 
  of 
  Some 
  Recently 
  Described 
  Minerals. 
  

   IIaudystonite 
  is 
  a 
  new 
  calcium-zinc 
  silicate 
  from 
  Franklin 
  Fur- 
  

   nace, 
  New 
  Jersey, 
  described 
  by 
  J. 
  E. 
  Wolff. 
  It 
  occurs 
  in 
  granu- 
  

   lar 
  crystallized 
  form, 
  showing 
  several 
  cleavages 
  interpreted 
  as 
  

   basal 
  and 
  prismatic. 
  Thin 
  sections 
  show 
  it 
  to 
  be 
  uniaxial 
  and 
  

   negative. 
  Hardness, 
  3 
  to 
  4 
  ; 
  specific 
  gravity, 
  3"396 
  ; 
  colorless 
  to 
  

   white, 
  with 
  vitreous 
  luster. 
  The 
  formula 
  deduced 
  is 
  Ca,,Zn8i,0., 
  

   obtained 
  from 
  a 
  number 
  of 
  analyses, 
  of 
  which 
  one 
  is 
  here 
  quoted. 
  

  

  SIO.. 
  ZnO 
  MnO 
  CaO 
  Mg(^ 
  FeoOg 
  ign. 
  

  

  BS-lb 
  'id-SO 
  ]-50 
  33 
  85 
  1-G2 
  0-57 
  0-52 
  = 
  100-4G. 
  

  

  