88 
REPORT—184/. 
case, should tfte height of the wave be considerable, it «iU assume more or 
less the character of an enormous breaker as it enters into shallower wafer 
in Its approach to the land. The first effect on shore will he that retirement 
of the water which mtiy be observed on a smaller scale, as the effect of everv 
ordinary wave immediately before it breaks on the beach: and soon afteV 
the great wave wall burst with overwhelming force upon the shore. Such 
attendant on gi^at earth- 
tfnl ^'7A- approximate determina¬ 
tion of the centre of disturbance, depending on tlio retardation of one of Uie 
two waves of vibratory motion proceeding from the same original disturb- 
ance, and we might in like manner avail ourselves of Uie diffe^nce between 
wavefamUh of propagation of either of these vibratoiy 
^^thp fw! V'llocity of the great sea wave, to deduce an accurate formuii 
for the determination of the distance of the centra- of dlverpciicc of the sea 
TWeloc K^Tlf subterranean eentr?of disturbance. 
w 1 beio 1?I ‘‘"y depth of the sea, 
will be 80 small compared with that of the vibratory wave, that it may suffice 
to consider the time of the arrival of the latter at the place of observation 
tl ns wL .1 Also let denote the vdociry of 
sea vvSo ZtWn "'f move if the depth of the 
miVZ nT tbe point of divergence 
mate dhLoe. betwee,, tl.'esetwo poIntetSf ‘ 
= «.^ 
proximate valu^TA^. means of ascertaining the ap- 
crust, and its jH>ssiblc effects on the Elevation of the Crust. 
in the suddenTevTionTf described has been supposed to originate 
produced by any sudden cxnan manifestly be equaUy 
dition being, ir7aTl cal S "'dbin the water itself, the con- 
suddenly as to elevate the tin,*.} •» P*'‘>ducing the wave shall act so 
before the internal fluid "nniediately over the seat of actioa 
this sudden action, has had timH'"'”*'" compression produced by 
parts of the fluid. A wave of ihn ^y P^'^'P^^galiou to other 
fluid mmss which we have sunnn -.vtT'** ^*”1 “dgJ»t also be produced in the 
If the crust wem diin tl.e earlhs solid crust, 
with nearly the same’ fatilitv o» irtfl'"’ ^ be produced 
free; but if, op the cllrarv ^ tbe fluid wei^ perfectly 
It would rcfjiiire an instami’nt'ous crTf ^ heavy and inflexible, 
elevate to any (ronsiderablo h#.if»bf ii. ^ action of enormous intensity to 
pressure slmuld be protnmitPiftri crust, before thefluid 
rapidity with wbid. t^pfo To «adeistand the 
take place, it must be obsirmJ that of fluid pressure will 
would Iiroduceastroiiir vihrnt.irr- explosive action here supposed 
wi'fi. .1.' i^*V to (he coniprcssioM ivonld that the incre^ 
