April i 2, 1906] 



NA TURE 



565 



Norway or other interesting- district, limited to 

 association ticket-holders. 



A handbook dealing- with the natural history and 

 archasologv of the York district has been specially 

 written for the occasion, and a copy will be presented 

 to each member of the association. 



It is anticipated that there will be a large amount 

 of private hospitality, and as so many members were 

 unable to visit South Africa last year il is expected 

 that there will be a very large meeting. 



THE ERUPTION OF VESUVIUS. 



''pHE activity of Vesuvius, incessant for some time 

 -* oast, has culminated in an eruption which, 

 making every allowance for newspaper exaggeration, 

 stands in the foremost rank of historic eruptions, even 

 if it is not already the greatest of all. It is not yet 

 at an end; we cannot say that it has reached its 

 climax; but the interest excited is so great that some 

 forecast of the future, so far as this is possible, may 

 be attempted. 



The late Prof. John Phillips pointed out that the 

 volcanoes of the Phlegrsean fields have had two periods 

 of activity, each lasting about four hundred years, and 

 that Etna has also had two great periods of activity, 

 the first of which lasted about 800 years, reaching its 

 maximum in the second century B.C., while the 

 second, commencing about the fourteenth century, had 

 attained its maximum about the end of the eighteenth, 

 after which eruptions declined in violence and fre- 

 quency ; from this he concluded that a period of 700 

 or 800 years may be assigned to the periods of volcanic 

 activity of Etna. It is probable that in all cases of 

 volcanic activity there is some such period, in which 

 the eruptions, spasmodic at first, increase gradually 

 in frequency until they attain a maximum, and then 

 die out again, the length of the period being deter- 

 mined by the size of the reservoir of molten rock 

 which gives rise to the eruptions; but there is not as 

 yet any means of determining what will be the dura- 

 tion of the present series of Vesuvian eruptions, or 

 whether it has reached its maximum ; all that seems 

 certain is that there are no signs of this being passed. 



Between A.D. 79,, when Pompeii was destroyed, and 

 1631, eleven great eruptions were recorded; the seven- 

 teenth century gave four, the eighteenth twenty-three, 

 and in the nineteenth, up to 1869, the date of Prof. 

 Phillips's work, twenty-four were recorded. After that 

 date there was the great eruption of 1872, and an 

 almost continuous condition of activity ever since. It 

 may be that we have now reached the climax, or the 

 future may have catastrophes in store still greater 

 than that which we are now witnessing; but, if there 

 is any virtue in analogy or inference, centuries must 

 elapse before the mountain resumes that condition of 

 quiescence which existed before our era, and for pro- 

 longed periods in the centuries which followed its 

 commencement. 



The length of these periods of volcanic activity and 

 the difference between those of neighbouring volcanic 

 centres shows that the cause lies deep in the earth, 

 and that the conditions are beyond our ken. Pro- 

 phecy must necessarily be vague, and can do no more 

 than indicate the future course of events in the most 

 general and guarded terms; yet mankind will always 

 want to peer into the future. Attempts will be made 

 to predict the time of coming eruptions, and not 

 wholly without justification, for extra-mundane con- 

 ditions must, to some slight extent, influence the 

 manifestations of volcanic activity. Prof. Palmieri 

 believed that there was a distinct increase in the 

 activity of ejection from the cone and in the abundance 

 of the lava at the new and full moon, and it is possible 



NO. IQ02, VOL. 73] 



that a connection exists with cycles of variation of 

 climate, magnetic force, or the frequency and distribu- 

 tion of certain solar phenomena, but the relation may 

 be only of the nature of the proverbial last straw 

 that broke the camel's back. On occasion it may do 

 so, but though sometimes the camel can bear many 

 more straws, at others he has given way before even 

 one was added to his load ; and so it is with volcanoes. 

 The cause of their eruptions is so preponderatingly 

 mundane that any slight effect of extra-mundane 

 causes must be elusive, difficult to establish, and only 

 to be detected by the study of a long series of averages. 

 For purposes of prediction they are of little use. 

 There is, however, some comfort for the immediate 

 future in the reported subsidence of Pozzuoli ; if real, 

 this probably indicates that the present paroxysm has 

 reached its climax, and will now slowly cease. 



From the Press reports of the eruption, the follow- 

 ing particulars of scientific interest have been ex- 

 tracted and arranged as a diary of events : — 



April 5. — Vesuvius in strong activity, (neat blocks of 

 rock hurled as far as the lower station of the funicular 

 railway. 



April 6. — The new crater began to emit lava in an 

 abundant stream. The lava has arrived within three or 

 four miles of the village of Bosco-Trecase. 



April 7. — Bosco-Trecase destroyed. After midnight loud 

 rumblings were heard, followed by a violent earthquake 

 shock, which shattered the windows in the town. Then 

 lava began flowing from Ciaramella, where a fresh fissure 

 had opened up a few days previously. From the Ciaramella 

 crater masses of incandescent rock were ejected, and a 

 torrent of lava swept down at a terrific speed, flowing in 

 two streams, one 200 yards broad moving towards the 

 centre of the town. The town had hardly been evacuated 

 whin the lava invaded the houses, several of which were 

 burned down, and soon Bosco-Trecase seemed to be 

 enveloped in flames. At 6 a.m. Bosco-Trecase was com- 

 pletely surrounded by a stream of lava. The cone on the 

 Pompeii side of Vesuvius collapsed, and on the opposite 

 side a new crater opened at the base of the cone in the 

 Atrio del Cavallo and vomited lava and stones. The prin- 

 cipal crater was in violent eruption. Explosions were 

 unceasing. A shower of grey-black ashes fell in the streets 

 of Naples. 



April 8. — Central crater of Vesuvius was again emitting 

 quantities of lava. Repeated explosions were followed by 

 subterranean rumblings and by earthquake shocks, which 

 were distinctly felt in the villages at the foot of the moun- 

 tain. At 12.31 a.m. a slight shock of earthquake was felt 

 at Naples, and a second at 2.10 a.m., both disturbances 

 being accompanied by rumblings. A telegram from Naples 

 at 6.30 p.m. announced that Ottajano, Poggio Marino, 

 and Somma had been entirely abandoned. At Ottajano 

 the lava was flowing 7 feet deep through the .streets. At 

 S p.m. the flow of lava seemed to be generally somewhat 

 slackening. A shower of black dust, like iron filings, fell 

 throughout Montenegro, covering the surface of the country 

 to a ctepth of a millimetre with an iron-grey layer. Prof. 

 Mattucci, director of the Vesuvius Observatory, made the 

 following report : — 



" The eruption of Vesuvius has assumed extraordinary 

 proportions. Yesterday and last night the activity of the 

 crater was terrific and ever increasing. The neighbour- 

 hood of the observatory is completely covered with lava. 

 Incandescent rocks are thrown up by the thousand to 

 the height of 2400 feet, and even 3000 feet, and fall back, 

 forming a large cone. Another stream of lava has appeared 

 from a fissure the position of which is not well defined. 

 The noise of the explosions and of the rocks striking 

 together is deafening. The ground is shaken by strong 

 and continuous seismic movements. The seismic instru- 

 ments threaten to break, and it will probably be necessary 

 to abandon the observatory, which is very much exposed to 

 electric shocks. The telegraph is interrupted, and it is 

 believed that the funicular railway has been destroyed." 



April 9. — The stream of lava in the direction of Torre 

 Annunziata has remained stationary since yesterday even- 

 ing. The dynamic action of the volcano appears to be 



