August 2, 1886.] 



♦ KNONATLEDGE ♦ 



301 



for their safety, took up arms and put a stop to further 

 op?rations." 



In the eruption of 1755 a singular ciroumstance occurred. 

 From the Yal del Bove, usually dry and arid, there flowed 

 a tremendous volume of water forming a stream two miles 

 broad, and in some places 3-i feet deep. It flowed in the 

 first part cf its course at the rate of two miles in three 

 minutes. It is said to have been salt, and many supposed 

 it had been in some way drawn from the sea, since its 

 volume exceeded that of all the snow on the mountain. It 

 lias, howe%'er, since been found that vast reservoirs of snow 

 and ice are accumulated in diflerent parts of the mountain 

 beneath the lava. The snow was melted by the heat of the 

 rising Hva, and was made salt by vaporous exhalations. 



Of the singular solidity of the walls of an advancing lava 

 stream, Recupero has related a remarkable instance. During 

 the eruption of 17C(5, he and his guide had ascended one of 

 those minor cones which lie, as we have said, on the flanks 

 of the mountain, and from the summit of this hill they 

 watched with feelings of awe the slow advance of a fiery 

 river two miles and a half in breadth. Suddenlv they saw 

 a fissure opening in the solid walls which encircled the front 

 of the current of lava ; and then from out this fissure two 

 streams of lava leaped forth and ran rapidly towards the hill 

 on which the observei-s were standing. They had just time 

 to make their escape, when, turning round, they saw the 

 hill surrounded by the burning lava. Fifteen minutes later 

 the foundations of the hill had been melted down, and the 

 whole mass floated away upon the lava, with which it 

 presently became completely incorporated. 



It would be a mistake, however, to suppose that such an 

 occurrence as the one we have just related is often observed. 

 On the contrary, it seems that when burning lava comes 

 into contact with rocky matter, the latter is usually very 

 little aflected. It is only when fresh portions of incandescent 

 lava are successively brought into contact with fusible rocks 

 that these can be completely melted. Sir Charles Lyell 

 quotes a remarkable story in illustration of the small eft'ects 

 which are produced by lava when there is not a continual 

 supply of fresh material in an incandescent state. " On the 

 site of Mompiliere, one of the towns overflowed in the great 

 eruption of 1 609, an excavation was made in 1 704 : and by 

 immense labour the workmen reached, at the depth of 

 35 feet, the gate of the principal church, where there were 

 three statues held in high veneration. One of these, 

 together with a bell, some money, and other articles, was 

 extracted in a good state of preservation from beneath a 

 great arch formed by the lava." This will seem the more 

 extraordinary when it is remembered that eight years after 

 the eruption the lava wa.s still so hot at Catania, that it was . 

 impossible to hold the hand in some of the fissures. 



Among the most remarkable of the eruptions of Etna 

 which have taken place in recent times are those of 1811 

 and 1819. 



In 1811, according to Gemmelaro, the great crater gave 

 vent, at first, to a series of tremendous detonations, from 

 which it was judged that the dome of the mountain had 

 become completely tilled with molten lava, which was seek- 

 ing to escape. At length a violent shock was experienced, 

 and from what followed it would seem that by this shock 

 the whole internal framewoik of the mountain had been 

 rent open. For, first, a stream of lava began to pour out 

 from a gap in the cone not far from the summit. Then 

 another .--tream burst out at an opening directlv under the 

 first, and at some distance from it. Then a third opening 

 appeared, still lower down ; then a fourth, and so on, until 

 no less than seven openings had lieen formed in succession, 

 all lying in the s;ime vertical plane. From the way in 

 which these openings appeared, and the peculiarity that each 



stream of lava had ceased to flow before the next lower one 

 burst forth, it is supposed that the internal framework of 

 the mountain had been rent open gradually, from the sum- 

 mit downwards, so as to sufler the internal column of lava 

 to subside to a lower and lower level, by escaping through 

 the successive vents. This, at least, is the opinian which 

 Scrope has expressed on the subject in his treatise on 

 " Yolcanoes." 



{To he continued.) 



SEA SERPENTS AND DRAGONS.* 



T would be difiicnlt to say which of the two 

 great classes of the unthinking do most mis- 

 chief — those who believe everything, or those 

 who believe nothing. Fnfortunately both 

 classes are very numerous, and far outnumber 

 those who believe only what they have reasoned 

 about, and have either leai-ned themselves or 

 received after due consideration from those whom they recog- 

 nise as competent to express an opinion. 



To the foolish who believe everything we owe the wide 

 prevalence of superstitions, from those of the most chOdish 

 nature, to those which seem to have an air of respectability 

 but in i-eality are only very ancient mistakes. To the 

 foolish who believe nothing we owe in like degree the pre- 

 valence of superstitions, many of them very stupid. If one 

 set oppose all discovery, all results of original thought, 

 because inconsistent with their beloved superstitions, the 

 other equally oppose aU new truths because ina)nsistent 

 with their narrow range of ideas. And although one might 

 imagine the opinion <:>f neither set to be of any importance, 

 unfortunately men are apt in such matters to count heads 

 rather than to weigh brains; and it is certain that the 

 number of those whose opinion has been of no weight has 

 enormously exceeded in all ages that of those who can 

 render a reason and are therefore worth listening to. 



This might matter little if only matters of scientific 

 interest were in question, but matters of political and reli- 

 gious importance are dealt with in the same foolish way. 

 The many who believe every absurd superstition, and the 

 many who believe nothing — the fatuously credulous and 

 the rampant!}' infidel — have done equal mischief to the 

 cause of true religion ; and the name of either class is legion, 

 as revivals and religious disputes alike testify. The many 

 who retain all the mistakes of past ages in matters political, 

 and the many who have no faith in any form of govern- 

 ment — the imbecile " subject " and the foolish anarchist — 

 have done equal mischief to the cause of true political pro- 

 gress, and of these also the name is unfortunately '• legion," 

 as the last general election (wherever and whenever it took 

 place) abundantly shows. 



^Ve may fairly take the conduct of men in some matter of 

 scientific inquiry as typical of their conduct in those more 

 important matters — politics and religion. The book before 

 us presents an interesting set of specimens, (1) of readiness 

 to believe everi/thimf ahoxit floods, dragons, .=ea-serpents, uni- 

 corns, and so forth, and (2) of the equally stupid incredulity 

 which has caused as many foolish persons of another class to 

 raise loud hee-haws when anything has been described which 

 was a little outside the familiar, and to believe in nothimj 

 new to them. 



Mr. Gould's introduction presents adminibly the general 

 argument in regard to credulity and incredulity. He per- 

 haps dwells a little too much on the tendency to ignoi-ant 



* " .Mythical Monsters." 

 Allen & Co. 



By Arthur Gould. London: W. H. 



