410 Chronicles of Science. [ July, 
its course along the line of the valley, having a heavy downthrow to 
the west, and that, in fact, the present depression was produced by 
a relative descent of the eastern side of the hill-district of Judea 
during the movements that raised the entire land from the sea.” 
The change in the surface-level of the Dead Sea, and the specula- 
tions on the causes which have contributed to lessen the volume of 
its waters, lead Mr. Smyth by an easy step to a discussion of the 
numerous facts which prove oscillations of climate during past 
geological periods, and to an examination of the theories which have 
been advanced in explanation of the phenomena of the Glacial 
Period in countries which now enjoy a comparatively warm climate ; 
and of a sub-tropical climate in Miocene times in regions which lie 
within the frigid zone of the Recent period. Considerable attention 
is given by the President to the familiar theory of the Swiss geo- 
logists, that the comparatively shrunken condition of the existing 
glaciers is due to the hot blast (called the Fohn or Scirocco) which 
keeps the snows and glaciers in check at the present day having its 
origin in the African deserts, while during the Glacial period this 
wind did not prevail in consequence of the deserts having then been 
submerged. It has, however, been shown by Professor Dove that 
the great bulk of the winds which descend hot, and full of moisture, 
on the Alpine regions has ascended from land and ocean far to the 
west of Africa. ‘The inconclusiveness of the Swiss theory has also 
been illustrated on other grounds by Sir Charles Lyell, who has, in 
this connection, called attention to the fact that the sea of the North 
African deserts continued to exist in Post-tertiary times. 
The possession, during the Miocene period, of a sub-tropical 
climate by the region of North Greenland, between the parallels of 
70° and 80° N., is even more difficult of solution, as at present it 
is generally allowed that changes in physical geography are, alone, 
insufficient to produce the effect, while the probable results of cos- 
mical changes are at present but slightly understood by geologists. 
With respect to subterranean temperatures, Mr. Smyth gives an 
interesting summary of the principal facts and opinions, and succeeds 
in producing the impression that all existing theories on the subject 
are somewhat premature; but he most happily describes the efforts, 
successes, and failures of geologists in comparing them to the 
incidents in a voyage of discovery. “The region we make for is one 
of vast extent ; and we sail on various courses and in very different 
varieties of craft. Some of us push rapidly forward in fast clippers ; 
others cleave their way slowly, and yet not always surely.” 
Of the papers contained in the ‘ Proceedings’ of the Society, we 
must first notice that by Sir John Lubbock, “On the Parallel Roads 
of Glen Roy,” in which the author objects to the commonly received 
opinion that these roads are the beaches, in the ordinary sense of the 
