﻿ACADEMY 
  OF 
  SCIENCES. 
  339. 
  

  

  " 
  The 
  bank, 
  which 
  is 
  composed 
  of 
  this 
  sand, 
  commences 
  at 
  a 
  per- 
  

   pendicular 
  bluff 
  at 
  the 
  southwest 
  end 
  of 
  the 
  island, 
  and 
  extends 
  one 
  

   and 
  a 
  half 
  miles 
  almost 
  due 
  south, 
  parallel 
  with 
  the 
  beach, 
  which 
  is 
  

   about 
  one 
  hundred 
  yards 
  distant 
  from 
  the 
  base 
  of 
  the 
  sand-bank. 
  

   This 
  sand-drift 
  is 
  about 
  sixty 
  feet 
  high, 
  and 
  at 
  the 
  extreme 
  south 
  

   end 
  the 
  angle 
  preserved 
  is 
  as 
  steep 
  as 
  the 
  nature 
  of 
  the 
  sand 
  

   will 
  permit. 
  The 
  bank 
  is 
  constantly 
  extending 
  to 
  the 
  south. 
  It 
  is 
  

   said 
  by 
  the 
  natives 
  that, 
  at 
  the 
  bluff, 
  and 
  along 
  the 
  middle 
  of 
  the 
  

   bank, 
  the 
  sand 
  is 
  not 
  sonorous. 
  But 
  at 
  the 
  extreme 
  south 
  end 
  and 
  

   for 
  half 
  a 
  mile 
  north, 
  if 
  you 
  slap 
  two 
  handfuls 
  together, 
  there 
  is 
  a 
  

   sound 
  produced 
  like 
  the 
  low 
  hooting 
  of 
  an 
  owl 
  — 
  more 
  or 
  less 
  sharp, 
  

   according 
  as 
  the 
  motion 
  is 
  quick 
  or 
  slow. 
  Sit 
  down 
  upon 
  the 
  sand, 
  

   and 
  give 
  one 
  hand 
  a 
  quick, 
  circular 
  motion, 
  and 
  the 
  sound 
  is 
  like 
  

   the 
  heavy 
  bass 
  of 
  a 
  melodeon. 
  Kneel 
  upon 
  the 
  steep 
  incline, 
  ex- 
  

   tend 
  the 
  two 
  hands, 
  and 
  clasp 
  as 
  much 
  sand 
  as 
  possible, 
  slide 
  rap- 
  

   idly 
  down, 
  carrying 
  all 
  the 
  sand 
  you 
  can, 
  and 
  the 
  sound 
  accumu- 
  

   lates 
  as 
  you 
  descend, 
  until 
  it 
  is 
  like 
  distant 
  thunder. 
  In 
  this 
  ex- 
  

   periment 
  the 
  sound 
  was 
  sufficient 
  to 
  frighten 
  our 
  horses, 
  fastened 
  a 
  

   short 
  distance 
  from 
  the 
  base 
  of 
  the 
  drift. 
  

  

  " 
  But 
  the 
  greatest 
  sound 
  we 
  produced 
  was 
  by 
  having 
  one 
  native 
  

   lie 
  upon 
  his 
  belly, 
  and 
  another 
  taking 
  him 
  by 
  the 
  feet, 
  and 
  dragging 
  

   him 
  rapidly 
  down 
  the 
  incline, 
  carrying 
  as 
  much 
  sand 
  as 
  possible 
  

   with 
  them. 
  With 
  this 
  experiment 
  the 
  sound 
  was 
  terrific, 
  and 
  could 
  

   have 
  been 
  heard 
  many 
  hundred 
  yards 
  distant. 
  With 
  all 
  the 
  ex- 
  

   periments 
  that 
  were 
  made, 
  it 
  seemed 
  the 
  sound 
  was 
  in 
  proportion 
  

   to 
  the 
  amount 
  of 
  sand 
  put 
  in 
  motion 
  with 
  a 
  proportionate 
  velocity. 
  

   Another 
  consideration 
  seems 
  requisite, 
  that 
  is, 
  its 
  perfect 
  dryness. 
  

   The 
  dry 
  sand 
  would 
  sound 
  on 
  the 
  surface, 
  where 
  six 
  inches 
  beneath 
  

   it 
  was 
  wet 
  ; 
  but 
  if 
  any 
  of 
  the 
  wet 
  sand 
  became 
  mingled 
  with 
  the 
  

   dry, 
  its 
  property 
  of 
  sounding 
  ceased 
  at 
  once. 
  The 
  sand 
  appears 
  to 
  

   the 
  eye 
  like 
  ordinary 
  beach 
  sand, 
  but 
  ordinary 
  beach 
  sand 
  will 
  not 
  

   produce 
  the 
  sounds. 
  It 
  has 
  been 
  said 
  that 
  it 
  lost 
  its 
  sonorous 
  prop- 
  

   erties 
  when 
  taken 
  away 
  from 
  the 
  bank. 
  But 
  I 
  can 
  discover 
  no 
  

   diminishing 
  of 
  its 
  sonorous 
  qualities, 
  even 
  with 
  the 
  bottle 
  uncorked, 
  

   and 
  we 
  have 
  had 
  rain 
  frequently, 
  and 
  an 
  atmosphere 
  more 
  than 
  

   ordinarily 
  moist 
  for 
  this 
  time 
  of 
  year. 
  Perhaps, 
  if 
  exposed 
  to 
  a 
  

  

  Proc. 
  Cal. 
  Acad. 
  Sci., 
  Vol. 
  V.— 
  22. 
  December, 
  1874. 
  

  

  