182 Jounston-Lavis—The Eruption of Vesuvius in April, 1906. 
Vesuvius. None are very satisfactory, and each writer has limited his explanation 
to one theory. One group of writers attributes it to a strong south-west wind, 
not having taken the trouble to apply to the neighbouring observatory of 
Capodimonte for accurate data, which I here append, and for which I must thank 
the director, Professor Semmola :— 
Royat Opservatory oF Capoprmontr, Naptxs, 1906. 
Winn. 
3 Barometric Pressure reduced to 
Fy 0° : 700 mm. + Direction. | Kilometres per hour. 
a ero 
9 a.m. | 3 p.m. | 9 p.m. | Pally 9 a.m. 3 p.m. 9p.m. |/9a.m.|3p.m.|9p.m. 
1 50:0 50:2 52°8 51:00 || N.N.W. | N.N.E. N.E. 17 17 10 
2 | 54:6 53°7 55°3 54°53 N. N.N.E. | N.N.E. |] 11 We 10 
3 56:1 55'8 57:0 66°30 || N.N.E. | N.N.E,. N.E. 28 22 | 24 
4 59°5 58°7 59°5 59°23 N.E. N.E. N.E. 15 19 17 
5 58°4 56°6 56°4 57°13 N. N.N.E. 8. 10 4 5 
6 55'1 54°2 54°4 54°57 N. N.N.E. | N.N.E. |} 12 13 13 
7 53°38 52°5 53°38 53°03 || N.N.E. N.E. N.N.E. || 17 20 16 
8 51:0 48-4 48°3 49:23 || N.N.E. | N.N.E. | N.N.E. || 17 20 18 
9 | 48:2 47°7 49°7 48°53 || N.N.E. | N.E. N.N.E. || 18 16 14 
10 | 50°8 51°7 54:0 52°17 || N.N.E. | N.E. N.N.E. |] 16 20 12 
11 56:9 56'7 574 57:00 N. S.W. | N.N.W. 7 15 8 
12 57:1 55°5 55°7 56°10 || N.N.W. | S. N. 3 6 9 
PRoFessor SEMMOLA. 
From this we glean that from the evening of the 7th till the evening of the 
9th a steady wind was blowing from the N.N. E. at the rate of from sixteen to 
twenty kilometres per hour. That this wind did exist in Ottajano is proved 
by the peculiar round holes and cracks in the glass windows, described by 
Profs. Bassani and Galdieri, and others, being limited to that aspect of the houses. 
Prof. W. Herbert Hobbs * explains this by the inrushing vorticose current around 
the rising column of hot gases. Others attribute this peculiar distribution of the 
ejecta to an oblique projection from the mountain, as this has been observed 
to occur on former occasions. Such a cause would explain dense fragments of 
some considerable size reaching, say as far as Ottajano, but would absolutely 
break down in solving the spreading of finer and finer lapilli and dust miles to 
* “ The Grand Eruption of Vesuvius in 1906.”’—Journ. Geol., Chicago, Oct.—Nov., vol. xvii., 1906. 
