Vividness 

 Volcanoes 



SCIENTIFIC SIDE-LIGHTS 



740 



the relations of the event to other events 

 preceding and succeeding it are not remem- 

 bered, this momentary illusion will persist. 

 We have all heard persons exclaim, " It 

 seems only yesterday," under the sense of 

 nearness which accompanies a recollection 

 of a remote event when vividly excited. The 

 most familiar instance of such lively re- 

 production is the feeling which we experi- 

 ence on revisiting the scene of some memor- 

 able event. At such a time the past may 

 return with something of the insistence of 

 a present perceived reality. SULLY Illu- 

 sions, ch. 10, p. 257. (A., 1897.) 



3664. VOID, SENSE OF, FROM LACK 

 OF CUSTOMARY SOUND Facts in Con- 

 sciousness, but Unheeded. When we first 

 come out of a mill or factory, in which we 

 have remained long enough to get wonted 

 to the noise, we feel as if something were 

 lacking. Our total feeling of existence is 

 different from what it was when we were 

 in the mill. ... A friend writes to me: 

 " I have in my room a little clock which does 

 not run quite twenty- four hours without 

 winding. In consequence of this, it often 

 stops. So soon as this happens I notice it, 

 whereas I naturally fail to notice it when 

 going. When this first began to happen 

 there was this modification: I suddenly felt 

 an undefined uneasiness or sort of void, 

 without being able to say what was the 

 matter; and only after some consideration 

 did I find the cause in the stopping of the 

 clock. C. E. MULLER, quoted by JAMES in 

 Psychology, vol. i, ch. 11, p. 456. (H. H. & 

 Co., 1899.) 



3665. VOLCANO AND EARTHQUAKE 

 IN CONJUNCTION It is a very general 

 opinion that earthquakes and volcanoes have 

 a common origin; for both are confined to 

 certain regions, altho the subterranean move- 

 ments are least violent in the immediate 

 proximity of volcanic vents, especially where 

 the discharge of aeriform fluids and melted 

 rock is made constantly from the same cra- 

 ter. LYELL Principles of Geology, bk. ii, 

 ch. 22, p. 245. (A., 1854.) 



3666. 



Shock and Erup- 



tion Simultaneous. One of the earliest rec- 

 ords of a severe earthquake and a volcanic 

 eruption occurring simultaneously is found 

 in the accounts of the destruction of Her- 

 culaneum and Pompeii. The throwing-up of 

 Monte Nuovo in the neighborhood of Poz- 

 zuoli was accompanied with a dreadful 

 earthquake. At the time of the eruptions 

 of Kilauea in 1789 the ground shook and 

 rocked so that persons could not stand. The 

 first eruption of the volcano Irasu, in Costa 

 Rica (1783), was accompanied by violent 

 earthquakes. The smoke and flames which 

 are said to have issued from the side of 

 Mount Fojo at the time of the Lisbon earth- 

 quake are regarded by some as having been 

 volcanic. Others thought that the phenom- 

 ena, rather than being" on the side of Fojo, 



which showed no traces of volcanic action, 

 had taken place in the ocean. At the 

 time of the great earthquake at Concepcion 

 (1835), whilst the waves were coining in, 

 two great submarine eruptions were ob- 

 served. One, behind the isle of Quiriquina, 

 appeared like a column of smoke. The 

 other, in the bay of San Vicente, appeared 

 to form a whirlpool. The sea-water became 

 black, and had a sulf urous smell, there being 

 a vast eruption of gas in bubbles. Many 

 fish were killed. With this same earthquake, 

 near to Juan Fernandez, about one mile 

 from the shore, the sea appeared to boil, 

 and a high column of smoke was thrown 

 into the air. At night flames were seen. 



In 1861, when Mendoza was destroyed and 

 10,000 inhabitants killed, a volcano at the 

 foot of which Mendoza is situated burst into 

 eruption. MILNE Earthquakes, ch. 16, p. 

 274. (A., 1899.) 



3667. VOLCANO, PROBLEMS OF 



THE A Fiery Flood Waves Hardened into 

 Rock. The lava-streams of active volca- 

 noes, those last stragglers of the preceding 

 powerful product of volcanic action, still 

 contain unsolved problems for geology and 

 mineralogy. We behold the lava breaking 

 forth from the crater, and the mass of fire 

 congealing into stone. Biased by the pre- 

 vailing error that we understand what is 

 being formed before our eyes, we suppose 

 that we understand the formation of the lava 

 rock. But, in fact, we are still far from 

 such insight. The lava flowing almost with- 

 out sound from the crevices, in a tough, 

 heavy stream, already contains completely 

 formed crystals. It gradually congeals, car- 

 rying flakes like a stream of ice. The quiet 

 flow of the lava at its egress is in peculiar 

 contrast to the racket and noise the stream 

 makes in its progress and near to its end. 

 Finally it becomes a wild aggregate, a pro- 

 cession of hills of glowing blocks of rock, 

 propelled and rolled forward by an invisible 

 hand. It is not a simple consolidation of 

 homogeneous masses; steam and gases are 

 active meanwhile, chemical processes are 

 taking place. The glowing fire gradually 

 disappears, but while the mass solidifies and 

 crystallizes heat is again liberated, and the 

 chemical processes may long continue after 

 everything upon the surface of the mighty 

 stream may be rigid and seemingly dead. 

 RATH Der Vesuv, eine geologische Skizze, in 

 Virchow und Holtzendorff's Sammlung ge- 

 meinverstdndlicher wissenschaftlicher Vor- 

 trage (Serie viii, p. 671). (Translated for 

 Scientific Side-Lights.) 



3668. VOLCANO, QUIESCENT De- 

 lusive Repose A Century of Quiet Sudden 

 Eruption. For nearly a century after the 

 birth of Monte Nuovo, Vesuvius continued in 

 a state of tranquillity. There had been no 

 violent eruption for 492 years, and it ap- 

 pears that the crater was then exactly in 

 the condition of the present extinct vol- 

 cano of Astroni, near Naples. Bracini, who 



