328 
SIR RODERICK I. MURCHISON’S ADDRESS. [May 24, 1858. 
Yolve questions of liigli importance to every one who speculates 
upon the causes which have operated in producing the chains of 
mountains, and corresponding depressions of the earth’s surface. 
Movement of Waves . — An original view of the undulatory move- 
ments of the sea and its currents has been published at Borne # by 
Commander Cialdi, of the Pontifical marine service, author of 
various other works of merit on analogous subjects.^ It is out of 
my sphere to judge the merits of the work of this ingenious author, 
who, whilst I write, has visited London, to conduct to the Tiber two 
small steamboats ; but I may briefly say, that after an elaborate detail 
of facts, drawn from the writings of a multitude of mariners, engineers, 
geologists, and others, to the number of nearly two hundred, and 
also citing his own long experience when in the Sardinian navy, 
he endeavours to counteract by such data the prevalent theory of 
eminent mathematicians, which does not admit of any real motion 
of transport in the molecules which constitute a wave, nor the 
power of waves at great depths. To give my hearers some idea of 
the main object of a work which has been highly commended by 
the Accademia dei Nuovi Leicei of Borne, as well as by the Academy 
of Venice, I here cite the author’s own words, as conveying his 
main views : — 
“I am convinced,” says Cialdi, “that the real motion of trans- 
lation (or driving movement) in an undulating mass of water 
always exists during violent winds and storms, whatever be the 
depth of the sea ; and that it also obtains in moderate weather, but 
only where the inferior, the lateral, or the frontal development of 
the wave finds an obstacle, at any distance whatever from the shore. 
I also maintain that the motion communicates itself to the whole 
mass that constitutes the wave, when the latter cannot develop 
itself; and that the intensity of the motion is greatest at the bottom 
of the sea, and least on the surface, when the depth of water is rela- 
tively small, and when the wave is not broken. I further main- 
tain that the effects of this motion are more or less perceptible 
according to the nature and form of the obstacle, the volume of the 
undulating mass, and the velocity of its propagation. Moreover, 
these effects must prove very complicated, and produce all the 
varied series of powerful phenomena that we observe on abrupt 
coasts, piers, breakwaters, and shelving shores.” 
* ‘ Cenni sul Moto Ondoso del Mare e sulle Correnti di esso, 1856.’ 
f ‘ Studi Idrodinamici Nautici e Commercial^ Roma, 1845 ;’ ‘ Sul Tevere e la 
Unione dei due Mari, Roma, 1847 ‘Studi sur Porto di Livorno, Firenze, 1853.’ 
