TRANSACTIONS. OF SECTION C. 749 
is prominent, but which, apparently, do comparatively little towards the building 
of permanent waves. 
In some cases (e.g. lava flow) where plastic material flows over a bed which 
behaves in a rigid manner, the free surface of the upper moving viscous body 
is thrown into waves which are analogous to the characteristic water-waves of 
shallow streams. 
The author has proposed the term Kumatology (xiua,a wave) for the co- 
ordinate study of the waves of the Atmosphere, Hydrosphere, and Lithosphere. 
Part I].—Deseription of Illustrative Photographs. 
. Rock-waves, from a specimen in the Geological Museum, Jermyn Street, 
. Ditto. 
. Lava-waves, Vesuvius, 
. Mud-wave over a stone, section on road up Vesuvius. 
. Rippled sand of definite wave-length left after a thunderstorm, Branksome, 
Dorset. 
6. Supposed imprint of skin of fossil fish, from a piece of sandstone in the 
British Museum of Natural History, Cromwell Road, the form being that given by 
the rippling of sand by two simultaneous sets of waves. 
7. Supposed fossil nests of tadpoles, from a piece of sandstone in the same 
museum, being the form given by the rippling of sand by three simultaneous sets 
of waves. 
8. Ripples of blown sand, Branksome, Dorset. 
9. Ripples of blown sand, Ismailia. 
10. A desert sand-dune in its steepest, or spraying, form, south side of Lake 
Timsah, 
11. Sand naturally assorted in a desert dune, from a sample collected by the 
author at Ismailia. (Micro-photograph slide made for the author by Newton.) 
12. Small dunes on a sandy foreland of the Nile, forming a train of waves, Jooking 
up-wind. 
Cre Co bo ee 
The following photographs illustrate the sorting and sizing of materials by the 
waves of the sea :— 
13. Mixed detritus, east of Chesil Beach. 
14. A photographic field of pebbles lying on the Chesil Beach. 
15. Seven sets of pebbles collected by the author on the Chesil Beach, arranged 
i comers so as to show the gradation of sizes from end to end of the 
each. 
16, 17, and 18. The sorting of shingle from sand by waves, and the consequent 
formation of ‘chevrons’ of shingle on the beach at Branksome, 
8. The Eruption of Vesuvius of 1898. By Tempest ANDERSON, I/.D., B.Sc. 
The author stayed about a week at the Hermitage on Vesuvius, in September, 
1898, when the eruption was about at its height. 
A lava cone has been thrown up at the entrance of the Atrio del Cavallo, the 
slopes of which reach to the foot of Sommaon the west side, the cone of Vesuvius 
on the east, and nearly to the Hill of the observatory on the 8. W., and a prolonga- 
tion of the latter, the Crocella, described as of great beauty, has beer entirely 
covered up. The eruption has been going on gently in this locality for about two 
years, but has never been very active. Small streams of lava have been almost 
constantly poured out, but they have all cooled and solidified before reaching the 
foot of the mountain, and consequently have assumed the form of a cone rather 
than a large sheet. 
The lava in the early part of the eruption had been of the corded variety. In 
September 1898, that which was being poured out was scoriaceous. 
Lantern photographs from negatives by the author were exhibited, some of 
which have been reproduced in the ‘ Alpine Journal, May 1899. 
