﻿FEB. 
  4, 
  1922 
  abstracts: 
  geology 
  71 
  

  

  potential 
  was 
  reversed 
  at 
  the 
  same 
  time 
  that 
  the 
  electrometer 
  showed 
  

   a 
  reversed 
  reading. 
  

  

  All 
  of 
  the 
  cells, 
  including 
  the 
  ordinary 
  type 
  of 
  dry 
  cell, 
  the 
  silver 
  

   chloride 
  cells 
  and 
  the 
  storage 
  cells 
  appeared 
  to 
  be 
  entirely 
  normal 
  after 
  

   being 
  thawed 
  out. 
  The 
  glass 
  test 
  tube 
  containing 
  the 
  storage 
  cell 
  was 
  

   not 
  broken. 
  

  

  The 
  experiments 
  in 
  the 
  range 
  25° 
  to 
  —72° 
  C. 
  answer 
  completely 
  

   the 
  practical 
  questions 
  which 
  prompted 
  the 
  investigation. 
  The 
  

   thermodynamic 
  theory 
  as 
  expressed 
  in 
  the 
  Gibbs-Helmholtz 
  equation 
  

   is 
  accurately 
  confirmed 
  by 
  the 
  measurements 
  on 
  a 
  storage 
  cell. 
  At 
  

   temperatures 
  down 
  to 
  —170° 
  C. 
  points 
  of 
  theoretical 
  interest 
  were 
  

   found. 
  These 
  suggest 
  that 
  potential 
  differences 
  of 
  normal 
  value 
  at 
  

   ordinary 
  temperatures 
  may 
  be 
  greatly 
  magnified 
  at 
  extremely 
  low 
  

   temperatures 
  when 
  the 
  current 
  is 
  vanishingly 
  small. 
  High 
  atmos- 
  

   pheric 
  potentials 
  sometimes 
  observed 
  may 
  have 
  some 
  relation 
  to 
  this 
  

   effect. 
  

  

  We 
  wish 
  to 
  thank 
  Dr. 
  L. 
  A. 
  Bauer, 
  Director 
  of 
  the 
  Department 
  of 
  

   Terrestrial 
  Magnetism, 
  for 
  his 
  courtesy 
  in 
  lending 
  us 
  the 
  electrometer 
  

   and 
  Dr. 
  Mauchly 
  for 
  assistance 
  in 
  taking 
  some 
  of 
  the 
  observations, 
  

   also 
  Dr. 
  E. 
  Buckingham 
  for 
  valuable 
  suggestions. 
  

  

  ABSTRACTS 
  

  

  GEOLOGY. 
  — 
  Deposits 
  of 
  manganese 
  ore 
  in 
  Montana, 
  Utah, 
  Oregon, 
  and 
  

   Washington. 
  J. 
  T. 
  Pardee. 
  U. 
  S. 
  Geo!. 
  Surv. 
  Bull. 
  No. 
  725-C. 
  Pp. 
  

   141-243, 
  pis. 
  4, 
  figs. 
  11. 
  1921. 
  

  

  The 
  demand 
  for 
  manganese, 
  created 
  by 
  the 
  World 
  War, 
  caused 
  the 
  de- 
  

   velopment 
  of 
  many 
  deposits 
  in 
  the 
  States 
  mentioned. 
  Those 
  at 
  Phillipsburg 
  

   and 
  Butte, 
  Montana, 
  which 
  became 
  the 
  most 
  productive 
  in 
  the 
  United 
  

   States 
  are 
  parts 
  of 
  the 
  quartz 
  veins 
  that 
  carry 
  silver 
  and 
  zinc. 
  They 
  were 
  

   formed 
  in 
  Tertiary 
  time 
  by 
  the 
  replacement 
  of 
  country 
  rock 
  by 
  manganiferous 
  

   carbonates 
  and 
  silicates 
  that 
  emanated 
  from 
  intrusive 
  granitic 
  magmas. 
  

   The 
  superficial 
  parts 
  of 
  the 
  deposits 
  have 
  been 
  oxidized 
  without 
  noteworthy 
  

   changes 
  in 
  their 
  manganese 
  content. 
  

  

  In 
  Utah 
  deposits 
  of 
  manganese 
  ore 
  related 
  to 
  metalliferous 
  veins 
  are 
  found 
  

   in 
  several 
  of 
  the 
  mining 
  districts. 
  In 
  the 
  Little 
  Grande 
  district 
  flat 
  lying, 
  

   lens-like 
  or 
  tabular 
  masses 
  of 
  manganese 
  oxides, 
  found 
  at 
  a 
  certain 
  horizon 
  

   in 
  the 
  Mesozoic 
  McElmo 
  formation, 
  were 
  deposited 
  originally 
  as 
  carbonate 
  

   associated 
  with 
  limestone, 
  gypsum 
  and 
  other 
  sediments. 
  In 
  the 
  later 
  Terti- 
  

   ary 
  they 
  were 
  uncovered 
  by 
  erosion, 
  oxidized 
  and 
  locally 
  concentrated 
  into 
  

   workable 
  bodies. 
  

  

  In 
  the 
  Lake 
  Creek 
  district, 
  Oregon, 
  manganese 
  oxides 
  fill 
  cracks, 
  pores, 
  or 
  

   other 
  cavities 
  in 
  a 
  Tertiary 
  volcanic 
  tuff. 
  The 
  manganese 
  was 
  deposited 
  by 
  

   descending 
  solutions, 
  but 
  its 
  origin 
  is 
  obscure. 
  Other 
  deposits 
  formed 
  by 
  

  

  