‘ 
Maj. Barnard on the Dynamic Theory of the Tides. 349 
but a density intermediate between these species. The saussu- 
ile examined by Thompson is apparently a petrosilex. 
By its great density and its composition, the euphotide of 
Mt. Rose is related to certain rocks in which a white garnet, re- 
sembling saussurite, is mixed with serpentine, with hornblende, 
and with a feldspathic mineral. ‘These ageregates associa 
a ophiolites, albitic diorites, and a rock made up of epidote 
th P heck oceur in the form of beds in the crystalline schists of 
*altered Silurian series in Canada.* 
—— 
Arr, XXXVIIL.— The Dynamic Theory of the Tides ; y Maj. 
J. G. Barnarp, A.M, Corps of Engineers, U. 8. A. 
IN his treatise on « Tides and Waves,” Mr. Airy uses in 
nee to Laplace's investigation of the tides, the following 
e: 
: . 
zs now, | from our thoughts the details of the investigation, we 
Tost “tts general plan and objects, we must allow it to be one of the 
‘ splendid Works of the greatest mathematician ie past age. 
cult: YY suppositions afterwards introduced); secondly, the general diffi- 
tating treating the motions of fluids; thirdly, the peculiar difficulty of 
Ucing this consi i j i i iv 
‘greater clas Onsideration. The last point alone, in our opinion, gives 
inequality coe for reputation, than the Sauat explanation of the long 
upiter and Saturn.” 
See ie 
MM, and avn ou yibutions to the History of Ophiolites, this Journal, [2], vol. xxv, 
