THE NORTHERN SEAS. 293 



ence of wliicli is admittecl by all the world, tlie circumataiiee indicated by 

 Laplace, namely, that the interior fluid below the lava upon which lloats 

 the continents is in a state of an elastic liqnid, that it is a kind of com- 

 pact gas, having for measure of its immense elasticity at the center the 

 weight of half the tliick?u\ss of the globe, all mechanical difficulties disap- 

 l^ear. The erosive action of steam and of gases is admirably treated in 

 these notices of the voyage. As to the supposition formerly entertained, 

 that steam might have raised the beds of continents, this could only have 

 taken place when the thickness of the solidified crust was ecpiivalent in 

 weight to fourteen or fifteen hundred atmospheres; that is to say, to the 

 luaxinuuu tension of steam. So that when the solid enveloix^ was more 

 than six kilometres (4 miles) in depth it could no longer be ruptured by 

 the subterranean steam. We now know that this envelope is more than 

 fifty or sixty feet in thickness. I have recently received from the royal 

 astronomer of Scotland, Mr. Piazzi Smith, son of the admiral who has 

 rendered that name so illustrious, a series of admirable photographs of 

 the lava of the peak of Tenerifte. We still seem to see here in these 

 excoriated masses the effect of the corrosive gases driven out by the 

 laboratory of volcanic action, through the Assures formed by the trem- 

 bling of the earth. In relation to these terrestrial convulsions, produced 

 by chemical action, we involuntarily recall the death of Pliny, suffocated 

 in the dense gaseous eruption of Vesuvius, in the first century of our 

 era. 



I leave with regret the picture of the primeval world given in one of 

 the scientific notices. If this excellent article were developed it would 

 make two fine volumes. The technical words, even, are rendered intel- 

 ligible. It shows us the earth progressing in form in j)roportion as it 

 cools, and pictures the ulterior forms of things. 



Et rerum i)aulatiui siimere foruias. 



It contains a representation — a very good one, I should think — of the 

 mode of action of the great geyser of Iceland, so closely observed l)y M, 

 Descloizeaux, which from time to time hurls into the air a column of 

 boiling water equal in diameter to the orifice of the pits of a large mine, 

 and in height to the towers of Notre Dame. Banks and Solander cooked 

 their fish in it. The merry band of Prince I^a[)oleon, sobered no doubt by 

 a ride of several hours on the gallop in the ram, followed by a bivouac in 

 damp clothing, with the exception of a punch made of the boiling water, 

 indulged in none of the eccentricities suggested by solemn British 

 phlegm. Our Frenchmen found at the geyser a tourist, a young Lord 

 Dufferin, with his tent, who had been waiting several days for one of 

 the paroxysms of the volcanic well. It seems the arrival of our travelers 

 decided the geyser; the fountain of boiling water shot up into the air 

 higher than could be measured by the eyes of the spectators, who were 

 stationed too near. The drawing of this beautiful phenomenon em- 

 bellished the public exhibition in the Palais lioyal. "Can it be cor- 

 rect!" asked the visitors, who examined this accurate crayon sketch. 

 In specifying what a geyser is, according to the theory Avhich Captain 

 Perri-Pisani oflers in regard to this volcanic eruption, I cannot do better 

 than compare it to an enormous manoscope of water, above the boiling- 

 point, when hurled into the air by the subterranean steam produced by 

 the volcanic fires. Hapi)ily it falls directly back into the tube froni 

 whence it was momentarily expelled. After this excursion a bill of 220 

 francs had to be paid for the grass eaten by the hundred horses of the 

 cavalcade. Grass is very rare and very dear in Iceland. But I must 

 confine myself to scientific facts. 



