﻿ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  55 
  

  

  accompany 
  earthquake 
  shocks. 
  This 
  was 
  followed 
  in 
  1847 
  by 
  

   another 
  report 
  to 
  the 
  British 
  Association 
  on 
  the 
  " 
  Facts 
  of 
  Earthquake 
  

   Phenomena." 
  His 
  first 
  paper 
  dealing 
  systematically 
  with 
  earth- 
  

   quakes, 
  and 
  in 
  which 
  he 
  propounded 
  his 
  dynamic 
  theory 
  of 
  earth- 
  

   quakes, 
  reducing 
  their 
  observed 
  phenomena 
  to 
  the 
  known 
  laws 
  

   of 
  wave-motion 
  in 
  solids 
  and 
  fluids, 
  appeared 
  in 
  the 
  ' 
  Transactions 
  

   of 
  the 
  Eoyal 
  Irish 
  Academy 
  ' 
  in 
  1848. 
  

  

  In 
  1850 
  Mallet 
  was 
  engaged 
  on 
  the 
  experimental 
  determination 
  

   of 
  the 
  limits 
  of 
  transit-rate 
  of 
  propagation 
  of 
  waves 
  of 
  impulse, 
  

   similar 
  to 
  those 
  of 
  earthquakes, 
  through 
  solid 
  substances. 
  His 
  re- 
  

   sults 
  are 
  recorded 
  in 
  the 
  fifth 
  volume 
  of 
  the 
  Trans, 
  of 
  the 
  Royal 
  

   Irish 
  Academy, 
  and 
  also 
  in 
  his 
  Second 
  Report 
  on 
  the 
  facts 
  of 
  

   earthquakes 
  to 
  the 
  British 
  Association. 
  The 
  velocities 
  of 
  trans- 
  

   mission 
  were 
  determined 
  in 
  wet 
  sand, 
  discontinuous 
  granite, 
  and 
  

   more 
  solid 
  granite 
  respectively, 
  on 
  Killiney 
  Strand 
  and 
  Dalkey 
  

   Island. 
  

  

  The 
  mean 
  velocities 
  obtained 
  were 
  : 
  — 
  

  

  In 
  wet 
  sand 
  824*9 
  ft. 
  per 
  second. 
  

  

  In 
  discontinuous 
  granite 
  .... 
  1306*4 
  „ 
  

  

  In 
  solid 
  granite 
  1664*57 
  „ 
  

  

  In 
  1860 
  Mr. 
  Mallet 
  carried 
  out 
  a 
  series 
  of 
  exhaustive 
  experiments 
  

   on 
  the 
  same 
  subject 
  ; 
  and 
  in 
  the 
  following 
  year 
  (1861) 
  he 
  communi- 
  

   cated 
  to 
  the 
  Royal 
  Society 
  full 
  detailed 
  results 
  of 
  his 
  investigations, 
  

   which 
  were 
  conducted 
  and 
  carried 
  on 
  at 
  Holyhead 
  during 
  the 
  progress 
  

   of 
  extensive 
  quarrying 
  for 
  materials 
  for 
  the 
  construction 
  of 
  Holy- 
  

   head 
  Harbour. 
  Enormous 
  blasts 
  were 
  fired 
  for 
  this 
  purpose, 
  and 
  

   the 
  effects 
  measured 
  by 
  means 
  of 
  specially 
  constructed 
  seismometers, 
  

   and 
  an 
  arrangement 
  of 
  time-recorders 
  started 
  and 
  stopped 
  by 
  elec- 
  

   tricity 
  ; 
  the 
  rate 
  of 
  wave-transmission 
  was 
  obtained 
  from 
  meta- 
  

   morphic 
  quartz 
  rock 
  and 
  slate. 
  

  

  Erom 
  1852 
  to 
  1858, 
  in 
  conjunction 
  with 
  his 
  son. 
  Mr. 
  Mallet 
  was 
  

   engaged 
  in 
  the 
  preparation 
  of 
  his 
  great 
  Earthquake 
  Catalogue 
  and 
  

   Seismic 
  Map. 
  

  

  In 
  1857 
  he 
  published 
  (in 
  two 
  volumes) 
  his 
  work 
  on 
  the 
  " 
  Great 
  

   Neapolitan 
  Earthquake 
  " 
  of 
  that 
  year, 
  and 
  also 
  communicated 
  to 
  the 
  

   British 
  Association 
  his 
  Report 
  on 
  the 
  Survey 
  and 
  Determination 
  of 
  

   the 
  Depth 
  of 
  the 
  Eocus 
  of 
  Impulse 
  and 
  the 
  Direction 
  of 
  Transmis- 
  

   sion 
  of 
  the 
  Elastic 
  Wave. 
  

  

  In 
  1859 
  he 
  was 
  elected 
  Fellow 
  of 
  our 
  Society 
  : 
  and 
  in 
  1864 
  the 
  

   honorary 
  degree 
  of 
  LL.D., 
  Trinity 
  College, 
  Dublin, 
  was 
  conferred 
  

   upon 
  him. 
  

  

  In 
  1862 
  Mr. 
  Mallet 
  published 
  his 
  'First 
  Principles 
  of 
  Observa- 
  

   tional 
  Seismology,' 
  a 
  development 
  or 
  extension 
  of 
  the 
  article 
  " 
  Earth- 
  

   quake 
  Phenomena" 
  which 
  appeared 
  in 
  the 
  Admiralty 
  Manual 
  of 
  

   Scientific 
  Inquiry. 
  One 
  of 
  the 
  finest 
  contributions 
  to 
  the 
  Physical 
  

   Geology 
  of 
  Volcanoes, 
  and 
  their 
  relations 
  to 
  Earthquakes 
  and 
  Moun- 
  

   tain-structure, 
  was 
  read 
  before 
  the 
  Royal 
  Society 
  in 
  1872, 
  and. 
  ap- 
  

   peared 
  in 
  1873. 
  This 
  paper 
  is 
  entitled 
  " 
  Volcanic 
  Energy, 
  an 
  attempt 
  

   to 
  develope 
  its 
  true 
  origin 
  and 
  cosmical 
  relations." 
  Mr. 
  Mallet 
  dis- 
  

  

  