10. REPORT—1858, 
Progressive rate of the shock, Lisbon earthquake of 31st March, 1761. 
Moment ee Time from 
‘ rom 5 ‘ 
Locality. observed | | sumed | impulse to} Observations. 
of shock. | Presut arrival. 
origin. 
Presumed focus, lat. 43°, h m Shia a 8 
NO a WS tectaasescceses ll 51 dap aes At Sea. 
Ship at sea, in lat. 43°, not 
many leagues from coast of 
DOCU gallo... -sraducaseassel es 11 52 0 30 L. a0 
Ship in lat. 44°, and about 80 
leagues off coast............ ll 54 1 45 3. 0 
COLUhNG L5,.6055.cesssscctaceecs Il 51 2 30 GIG 
Ship lat. 44° 8’, and 80 
leagues W.N.W. of Cape 
HMist€rre, —.c.<<esssa0sseo eee ll 58 3 30 “iy OU 
TASDON ciscacsasecetesssscneancee noon 4 30 Cn!) 
Madeira ...... hiiihccstdtwasers a rt as 15 0 
OGH site nddcen feavl) 1S) #LE 9 30 20 0 
11 40 20 O 
Loch Ness, between ........- and io and Uncertain. 
12 40 49 0 
fi 1s (84 0 
Amsterdam, between ......... and 15 15 and Uncertain. 
1 45 114 0 
The great sea-wave of the shock of 1755 appears, from the recorded 
periods of arrival, to have travelled from its point of origin to the following 
places at the rates given in miles English per minute, according to Milne ; 
assuming the transit rate uniform for the whole range of translation, which, 
however, is not possible :— 
Plymouth...... 4h rete -.+.+. 21 miles per minute. 
Kinsale... . 3 ee -e nit Stee TIRE 27 5 
Mount’s Bay .....% ee ee on eT 53 
COGS as és 3s cpsbee Te seis BO 9» 
Funchal A.s4s:ckef¥s Bee obs (B'7, 49 
Ayamento’ . 40. .6 553. Den epew airs vO 9 
Lisbon ..... eT ey eee 55 ” 
Antigua ts 1a. ots de 24 bb. (OO ” 
Barbadoes®? ..@% <4 «Wac¥eces de. 9'3 
ahd that of the shock of 1761, as follows :— 
Scilly Isles and Mount’s Bay.... 20 miles per minute. 
Dublin ect: ee ee ae we Bl ” 
Kinsaley . 0°..@5 4 see eee nd m 
Barpaddes ..\4.06. ees Medes ve 74 3 
I place these results of Milne’s discussions of the imperfect materials at 
his command, rather for convenience of reference to future investigators, . 
than as attaching much value to them beyond rude and provisional ap- 
proximations*. 
* For the same reasons I transcribe the following notice, which has appeared while these 
sheets have been printing :— 
“ Direction and velocity of the earthquake in California of the 8th and 9th J anuary 1857, 
By Dr. John B. Trask.” Silliman’s Journal, Jan. 1858, vol. xxv. p. 146. 
“The precise time of one of the shocks was obtained with tolerable accuracy for five 
