October 6, 1892] 



MA TURE 



547 



give the impre-ision of an eartliquake, so that several 

 times the people of these towns have rushed out into the 

 streets. On July 14 I observed in Acireale that the large 

 undulations of the air-blows which were propagated 

 bevond 333 m. per second, like sonorous vibrations, often 

 arrived unaccompanied by noise, and strongly shook doors 

 and windows. 



These reports, these air-blows, and the abundant ejec- 

 tion of incandescent lava still further prove that in No. 2 

 crater there was pasty lava which swelled and burst, as 

 we deduced from its effect on the white vapours. 



This period of great activity, in which the thick shower 

 of lava fragments projected from the different craters to 

 great heights, and spread over an area of 500m radius, 

 reached its macimuni about midnight, and then gently 

 declined a little. In the same manner the eruption con- 

 tinued during the following days with great energy, but 

 with a very gradual diminution in its intensity, inter- 

 rupted mire or less Dy strong spasms. The lava con- 

 tinued to advance, but diminished in velocity, while it 

 extended in breadth and depth. The eastern branch very 

 soon stopped, and also the western one, after having 

 continued its destruction of very fertile ground. This 

 having crossed the road known as the -St. Leo, finally 



Monti Crater Crater Crater Crater 



Nero. -.No. 4.5:No. 3. No. 2. No. %. 



Fig. 8.— Taken by G. Platania on July 30 from the north-east of the craters, 

 No. 4 is still very little, but in part hidden behind a prominence of the 

 ground. 



stopped, whilst the new lava that continues to issue forms 

 new ramifications and flows, which pass quite close to 

 the earlier ones, and now actually are in contact with 

 them, increasing the area covered. In the first paroxysm 

 of the eruption the lava issued in great gushes all along 

 the rift. Soon at "the upper part commenced the dejec- 

 tion cones, and lower down the fire vents, and the lava 

 flowed in abundance, and with explosions also in points 

 where now are the craters, as, for example, Nos. 3 and 4. 

 Later, when the explosive force had diminished, the lava 

 issued without explosions, almost silently from different 

 vents at the south end of the fissure on which are aligned 

 the craters. These vents, therefore, have during the 

 eruption varied in number and form. Some have assumed 

 the function of dejection cratersas occurred in Nos. 3 and 4, 

 which gave passage to much lava as a current. Qthers have 

 ceased to eject scoria, to send forth only torrents of lava, 

 as, for example, the little mouth to the east of No. 4, 

 the scoria rim of which exists only to the north, of about 

 20m. high, whilst the south rim has been swept away by 

 the current. Some of the mouths have been refilled by 

 the lava flows, and whilst some have become extinct 

 new ones have been formed. 

 In the last week of July, crater No. 2 assumed, for 

 NO. I 197, VOL. 46] 



some days, a new phase. Its explosions had become 

 rare, long, and very grand, and the large mass of vapour, 

 mixed with dust, brought back to my mind the eruption 

 of Vulcano when we stood on the crater edge and watched 

 and photographed the whole process, and stood our 

 ground amidst showers of bombs and other projectiles 

 (1888-90).^ By this it lost the beautiful regular truncated 

 cone form that it had at the beginning, and became 

 irregular and broken-down towards the north, like No. i. 



At the commencement of August the eruption already 

 seemed much diminished, craters No. i and 2 had 

 ceased to eject stones little by little, gradually becoming 

 blocked, and the enclosed lava was slowly cooling. In 

 fact, on the recommencement of a period of renewed 

 energy, the explosive force could no longer find an escape 

 by them, so that on August i a new crater opened in a 

 point higher up where the cleft to the west, which had 

 only acted at the commencement of the eruption, joined 

 a 'Other great rift on which the craters were formed. 

 Then on August 9 occurred another violent eruptive 

 spasm, which could not clear away the material that ob- 

 structed the ci-aters, but opened a new way, always on 

 the main cleft, between Nos. i and 2, and exactly at the 

 north base of the last of these craters. Here a little 

 funnel-shaped depression was formed which for a short 

 time ejected enormous masses. This new crater, how- 

 ever, soon passed into the solfataric stage as Nos. i, 

 2, and 3, and there remained in an energetic state of 

 activity only the crater of August 1 1 and No. 4. That one 

 which on August 2 1 measured in diameter only about 

 50 m., and had a height of about 60 m., later became 

 elongated towards the S.S.W., and its grand and beauti- 

 ful explosions, which I watched quite closely, in com- 

 pjany with Mr. Rudler, on August 29, 30, and 31, 

 were specially localized on the southern edge, so that 

 they tended all the more to give it an elongated form on 

 that more western cleft that was only in activity the first 

 days of the eruption. No. 4, meanwhile, which I ap- 

 proached, ascending upon No. 3, gave forth frequent 

 eruptions of hot lava cakes at regular intervals (about fifty 

 per minute), accompanied by globes of yellowish vapour, 

 and a noise similar to that which accompanies the globes 

 of vapour from the locomotive when it commences to 

 move. 



By unanimous consent of all the studious inhabitants 

 of Etna, the new craters have been called the Monti Sil- 

 vestri, in honour of that well-known vulcanologist, the 

 lamented Prof. Orazio Silvestri, who studied our volcano 

 with so much fervour, registered so assiduously every 

 slight disturbance, and described its paroxysms so well 

 and with such originality, that his loss has been deeply 

 felt by all men of science. Gaetano Pl.\tania. 



14, Via S. Giuseppe, .'\cireale, 

 September 7. 



NOTES. 

 The Harveian oration will be delivered by Dr. J. H. 

 Bridges at the Royal College of Physicians on Tuesday, 

 October 18, at four o'clock. 



The Medical Session in London was opened on Monday, and 

 introductory addresses were delivered in some of the schools 

 attached to hospitals. A particularly interesting and suggestive 

 address was delivered at the Westminster Hospital by Dr. 

 Mercier, who dealt with various aspects of the problems con- 

 nected with crime, pauperism, and insanity. Sir John Lubbock 

 addressed the students at St. Thomas's Hospital. 



On Friday last Sir George Murray Humphry, F.R.S., de- 

 livered an interesting address at the opening of the first sosion 



« "South Italian Volcanoes," by Johnston-Lavis, Naples, 1891. 

 ettili Squarciati di Vulcano," by G. Pbtania. (Roma, 1891.) 



