﻿ACADEMY 
  OF 
  SCIENCES. 
  307 
  

  

  Donations 
  to 
  the 
  Museum 
  : 
  A 
  collection 
  of 
  ancient 
  pottery, 
  the 
  

   specimens 
  artistically 
  wrought 
  and 
  perfectly 
  preserved, 
  was 
  ex- 
  

   hibited. 
  The 
  Vice 
  President 
  stated 
  that 
  the 
  collection 
  had 
  lately 
  

   been 
  consigned 
  to 
  him 
  for 
  the 
  Academy, 
  but 
  no 
  communication 
  in 
  

   reference 
  thereto 
  had 
  yet 
  reached 
  him. 
  It 
  was 
  believed 
  that 
  the 
  

   specimens 
  came 
  from 
  Peru, 
  and 
  had 
  been 
  sent 
  by 
  Benjamin 
  Smith 
  

   or 
  James 
  Freeborn, 
  two 
  members 
  of 
  the 
  Academy 
  who 
  are 
  now 
  

   traveling 
  in 
  South 
  America. 
  W. 
  H. 
  Turner 
  presented 
  the 
  pupa 
  

   of 
  a 
  large 
  species 
  of 
  beetle, 
  native 
  of 
  Mexico. 
  Mr. 
  Chapman 
  

   presented 
  specimen 
  of 
  Suisun 
  marble. 
  W. 
  N. 
  Lockington 
  donated 
  

   three 
  cases 
  of 
  insects. 
  D. 
  W. 
  C. 
  Gaskell, 
  of 
  Forbestown, 
  left 
  on 
  

   exhibition 
  remarkably 
  well-preserved 
  teeth 
  of 
  the 
  mastodon 
  ; 
  also, 
  

   tusk 
  of 
  a 
  fossil 
  elephant, 
  found 
  at 
  New 
  York 
  Flat, 
  Yuba 
  County, 
  

   found 
  in 
  auriferous 
  gravel, 
  on 
  the 
  bedrock, 
  fifteen 
  feet 
  below 
  the 
  

   surface. 
  

  

  Donations 
  to 
  the 
  Library 
  : 
  George 
  C. 
  Hitkox 
  presented 
  an 
  an- 
  

   tique 
  volume 
  entitled, 
  " 
  A 
  Catalogue 
  and 
  Description 
  of 
  the 
  

   Natural 
  and 
  Artificial 
  Rarities 
  belonging 
  to 
  the 
  Royal 
  Society, 
  and 
  

   Preserved 
  at 
  Gresham 
  College, 
  by 
  Nehemiah 
  Grew, 
  M.D., 
  Fel- 
  

   low 
  of 
  the 
  Royal 
  Society 
  and 
  of 
  the 
  College 
  of 
  Physicians, 
  Lon- 
  

   don. 
  Printed 
  by 
  W. 
  Rawlins 
  for 
  the 
  author, 
  1681." 
  

  

  Improved 
  Method 
  of 
  Observing 
  Altitudes 
  of 
  the 
  Sun 
  at 
  Sea. 
  

  

  BY 
  T. 
  J. 
  LOWRY, 
  U. 
  S. 
  COAST 
  SURVEY. 
  

  

  The 
  science 
  and 
  art 
  of 
  navigation 
  stand 
  among 
  the 
  proudest 
  achievements 
  of 
  

   modern 
  thought 
  and 
  research. 
  The 
  accurate 
  determination 
  of 
  the 
  places 
  of 
  

   the 
  fixed 
  stars, 
  and 
  of 
  the 
  motion 
  and 
  position 
  of 
  the 
  members 
  of 
  the 
  solar 
  sys- 
  

   tem, 
  gave 
  the 
  navigator 
  numerous 
  well 
  determined 
  points 
  for 
  observation. 
  But 
  

   the 
  attainment 
  of 
  a 
  corresponding 
  perfection 
  in 
  fashioning 
  instruments 
  has 
  ever 
  

   baffled 
  human 
  skill, 
  and 
  ever 
  will. 
  For 
  although 
  we 
  are 
  entitled 
  to 
  look 
  for 
  

   wonders 
  at 
  the 
  hands 
  of 
  the 
  artist, 
  we 
  cannot 
  expect 
  miracles 
  ! 
  And 
  we 
  hence 
  

   see 
  that 
  the 
  demands 
  of 
  the 
  astronomer, 
  and 
  even 
  the 
  nautical 
  astronomer 
  or 
  

   navigator, 
  will 
  always 
  surpass 
  the 
  power 
  of 
  the 
  instrument 
  maker. 
  They 
  must 
  

   therefore 
  so 
  combine 
  their 
  observations, 
  so 
  familiarize 
  themselves 
  with 
  all 
  the 
  

   causes 
  which 
  may 
  produce 
  instrumental 
  derangement, 
  and 
  with 
  all 
  the 
  peculiari- 
  

   ties 
  of 
  structure 
  and 
  material 
  of 
  each 
  instrument 
  used, 
  as 
  not 
  to 
  allow 
  them- 
  

   selves 
  to 
  be 
  misled 
  by 
  its 
  errors, 
  but 
  to 
  extract 
  from 
  their 
  indications 
  all 
  that 
  

   is 
  true 
  and 
  reject 
  all 
  that 
  is 
  erroneous. 
  

  

  It 
  is 
  true 
  that 
  the 
  astronomer 
  can 
  so 
  weigh 
  his 
  observations 
  in 
  the 
  balance 
  of 
  

   Proc. 
  Cal. 
  Acad. 
  Sci., 
  Vol. 
  V.— 
  20. 
  Decembek, 
  1874. 
  

  

  