14 



NATURE 



[May 3, 1888 



obtainable. Here, under very great difficulties, from the 

 looseness of the ground of about two square metres upon 

 which we stood, an attempt was made to take two instant- 

 aneous photographs of the crater as we looked down into 

 it. Unfortunately, both of these were useless, as we foresaw, 

 from the vapour blowing towards us. 



The crater was very quiet, only throwing out a very 

 few fragments of pasty lava cake, with about four or five 

 explosions during the four hours we remained near by. 

 There were other explosions, but too weak to eject any- 

 thing. I descended to the crater edge, but could not 

 remain long, on account of the heat of the ground and the 

 acid fumes, which seemed to be in great part composed of 

 HC1 with a good dash of S0 2 . 



On returning from the crater edge and descending a 

 little lower on the south-west of the Sciarra, a good view 

 is obtainable of that slope and the crater. Here two 

 successful photographs were taken, which show very well 

 the crater with its relative position to the summit of the 

 mountain and to the Sciarra. On the following day the 

 tour of the island was made in a boat, and, as only a 

 few stones were being ejected, we were able to land on 

 the narrow ledge or beach at the foot of the Sciarra. 

 Two successful photographs were taken from the Scoglio 

 dei Cavassi, from which a fine view is obtainable of the 

 Sciarra and the crater. 



During our residence on the island, and our stay at 

 Salina and Panaria, we always noticed that the amount 

 of visible vapour issuing was in direct proportion to the 

 humidity of the atmosphere. On account of the great 

 quietness of the volcano, it was impossible to form any 

 judgment as to whether there was any relation of increased 

 or diminished activity to the barometric pressure, and so, 

 indirectly, to the winds. 



Since leaving the island, correspondence has been kept 

 up between Signor Giuseppe Rende, the post and 

 telegraph master, and myself. The following information 

 I have been able to glean from that gentleman's letters. 

 From June to November 1887 the volcano remained in its 

 normal state. On November 18, a moderate eruption 

 (eruzione mediocre), and the wind blowing from the west, 

 a shower of scoria {? fragments) (aride pietre), fell amongst 

 the vines near the village. This was accompanied by 

 explosions (<W//), which, it appears, considerably frightened 

 the people. Later, the scoria (pomice) fell into the sea, 

 which it covered as far as the eye could see. Un- 

 fortunately, Signor Rende did not preserve any of the 

 £jectamenta, but, judging from what one sees composing 

 recent deposits of the island, the material was a pumiceous 

 scoria, or a light scoria, as it appears to have floated on 

 the sea. 



In answer to further inquiries, Signor G. Rende tells 

 me that the floating scoria extended eastwards as far 

 as the eye could reach. No lava appeared, but a small 

 mouth opened at the edge of the crater, but in a very few 

 days disappeared. He then goes on to say : — 



" I draw your attention in this letter to a very remark- 

 able fact. On the 25th of last February (i.e.1888), at 4.21 

 p.m., occurred two little shocks of earthquake of tin- 

 dulatory character, followed by a subsultory one, so that 

 we thought it would be the end of the world for us. 

 Never had a subsu'tory earthquake been felt. It split 

 various houses, overturned walls, and made earth-banks 

 slip. Those who had their eyes fixed on the mountain 

 seemed to see the summit of it fall over from south to 

 north. People who were working amongst the vines fell 

 on their faces. No victims. Neither Panaria, Lipari, nor 

 the other islands noticed the shock. The volcano {i.e. 

 Stromboli) was in no way affected (non fece mossa 

 alcuna)." 



Prof. Mercalli has collected together what is known 

 of the history of Vulcano and Stromboli. He also 

 published accounts of the state of these volcanoes during 

 the years 1882-86 inclusive (" Natura delle eruzione dello 



Stromboli," Atti della Soc. Ital. di Sc. Nat. vol. xxiv. ; 

 " Notizie sullo stato attuale dei vulcani attivi Italiani," 

 ibid. vol. xxvii. ; " La fossa di Vulcano e lo Stromboli dal 

 1884 al 1886," ibid. vol. xxix.). 



The eruption of November 18, 1887, is curiously near 

 the date of November 17, 1882, when one of the strongest 

 modern eruptions of Stromboli occurred, and when five 

 lateral mouths opened on the Sciarra about 100 metres 

 below the crater edge, but without the ejection of a lava 

 stream. As on one or two other occasions, the last erup- 

 tion extensively covered the sea with scoria, a fact of 

 no small importance when we take into consideration that 

 .Stromboli is a very basic volcano, in a unique state of 

 chronic activity, and is yet able to produce scoria or 

 pumiceous scoria, sufficiently vesicular to float on the sea, 

 and so be transported to great distances. 



With regard to the position of lateral eruptions of this 

 mountain, the only situation in which dykes are visible is 

 on the north-west side and near the Sciarra, where a con- 

 siderable number are to be seen. One of these is visible 

 in section near La Serra, showing it continuous with a lava 

 flow that oozed from it only a few metres above sea-level, 

 indicating that not very long since a lateral eruption gave 

 rise to a lava stream ; another, close to the crater, stands 

 out as a great wall at right angles to the present eruptive 

 axis of Stromboli, and certainly must have been formed 

 when the crater was at a very much higher level. No less 

 than three dykes at Stromboli are hollow ones, with their 

 interspace filled in from above by loose materials, show- 

 ing that they must also have been drained below present 

 sea-level, as they reach — as hollow dykes — down to the 

 beach. I believe I was the first to draw attention to this 

 peculiar variety of dyke, in describing the eruption of 

 Vesuvius of May 2, 1885, where it was possible to watch 

 the process of formation (" L'Eruzione del Vesuvio nel 

 2 Maggio, 1885," Ann. d. Accad. O. Costa d'Asp. Natu- 

 ralistic Era 3, vol. i. ; and " Lo Spettatore del Vesuvio," 

 Napoli, 1887). These hollow dykes of Stromboli may be 

 seen at La Serra, the northern limit of La Sciarra, and at 

 Punta Labronzo. I expected them to be rare, as there is 

 no mention of them made in any literature known to 

 me ; but as it is also well shown near the Punta del 

 Corno, at Vulcano, it can hardly be the case. 



In conclusion, I take this opportunity of thanking 

 Signor Narlian, of Vulcano, and Signor Rende for their 

 past kindness, and for the promise of further notes on 

 these two isolated, neglected, but interesting volcanoes. 



H. J. Johnston Lavis. 



HEAD GROWTH IN STUDENTS AT THE 

 UNIVERSITY OF CAMBRIDGE. 1 



T N the memoir read by Dr. Venn, on April 24, at the 

 J- Anthropological Institute, upon the measurements 

 made, during the last three years, of the students of Cam- 

 bridge, one column is assigned to what he terms " Head 

 Products," and which may fairly be interpreted as " Relative 

 Brain Volumes." The entries in it are obtained by multi- 

 plying together the maximum length and breadth of the 

 head and its height above a specified plane. The product 

 of the three determines the contents of a rectangular box 

 that would just include the portion of the head referred to. 

 The capacity of this box would be only rudely propor- 

 tionate to that of the skull in individual cases, but ought 

 to be closely proportionate in the average of many cases. 

 The relation they bear to one another affords, as it seems 

 to me, a trustworthy basis for the following discussion, 

 especially as all the measurements were made not only on 

 a uniform plan, but by the same operator. 



1 Read at the Anthropological Institute, on April 2A, by Francis Galton, 

 F.R.S. 



