HARDWICKE'S SCIENCE-GOSSIP. 



221 



To the left lies the transported boulder of reddish 

 i\!itll1 granite under which I sheltered resting on the 

 erupted rock which is of two sorts. That fronting 

 the bay, much resembling gutta percha in appearance, 

 rises into cindery heaps full of large pores like boil- 

 ing tar, soup, or other seething viscous matter ; the 

 rest smooth and compact, represents the lower portion 

 of the flow cooled without contact with the atmos- 

 phere ; and subsequently laid bare. In either case, 

 the fantastic pyramidal shape of the upper or de- 

 cidedly columnar form of the lower portion, may be 

 remarked ; the former seeming to indicate the stream 

 has welled up at the spot. The contraction of the 

 entire mass into rectangular masses is likewise notice- 

 able, but the exact analysis of the trachytic rock I 



for the waves to channel fresh beach lines with white 

 " chucky stones," where around their already terraced 

 flanks so many a shell has mourned its parent sea ? 

 The Phlegrsean fields resound to the work of the 

 Cyclops. Vesuvius smokes or Ischia shakes ; the 

 shore at Puzzuoli subsides ; Monte Nuovo too has 

 arisen in 153S ; but the wild braes of Argyleshire no 

 longer tremble to the earthquake forces that gave 

 them birth. Has the line of disturbance gone east- 

 ward where the shores emphatically rise and sink, 

 and where, off the rugged coast of Norway, a volcano 

 sprang from the sea in 1783 ; but if so, why has it 

 also lost its intensity ? 



Regarding the very origin of earthquakes and 

 volcanoes, of the undulations of the earth's sur ace 





- -S' " f> . 



y'^ C? 







Fig. 127. — Extinct Volcano, Isle of Mull. 



must leave to those who make a speciality of the 

 thing. Then what is its age ? Older than the time 

 when the boulder was brought and perched on it, 

 I think it must be, and here is the glacial epoch ; 

 but' must we wander back in thought to the earlier 

 period when that wondrous lava-stream boiled out at 

 Staffa, or its counterpart pouring through the chalk 

 formed the Giant's Causeway ? This, I think, is not 

 proven. 



But who that has walked over a lava stream, can 

 resist a feeling of awe as the cinders break like slag 

 beneath his feet, or can quench that desire to pene- 

 trate deeper into the mystery ? Why, one is tempted 

 to exclaim, do earthquakes shake so feebly this spot 

 once their own ; why do they not break forth in floods 

 of lava as heretofore, or heave up the flanks of Jura 



marked by raised shore line, sunken valley, and hill 

 and mountain, what sad discrepancy of opinion still 

 exists I The chemist pretty well since the time of 

 Lucretius has talked much and long of ignition or 

 oxidation, of chemical unions, of the explosion of 

 percolating water, and expansion of air or gases 

 generated within. The cosmologist since the days 

 of Humboldt at lea^t, has occupied himself with the 

 contraction of the scum on the surface of a molten 

 globe that is continually cooling and squirting out 

 as it contracts ; eliminating in his investigation a 

 variable element in a thin expansible crust, affected 

 by the sun's heat and unaffected by that of the interior, 

 and not exceeding 100 feet in thickness. The astro- 

 nomer has found a still newer theory in that of M. 

 Cordier {" Principles of Geology," v. il, p. 433-447) 



