46 



NA TURE 



[May 12, 1904 



flint glass and of the glass of which ordinary German tubing 

 is made, as well as that of mercury, have been included for 

 purposes of comparison. The compressibility of mercury 

 rests upon a large number of observations made in the 

 Challenger (Chem. Soc. Joiinu, 1878, vol. xx.xiii. p. 453). 



Table I. — Summary. 



It is pointed out that the number of metals experimented 

 on is too small to permit any confident generalisation. 



It will, however, be observed that in the case of the five 

 metals used as wire, their compressibility increases as their 

 density and atomic weight diminish, yet there is no reason 

 to suppose that the compressibility is a continuous function 

 of the atomic weight, like the specific heat. Mercury, 

 although in the fused state, shows this clearly. But besides 

 this, it happens that two pairs out of the five metals, namely, 

 platinum-gold and aluminium-magnesium, are contiguous 

 in the atomic weight series, yet the compressibility of mag- 

 nesium is, roughly, double that of aluminium, and the 

 compressibility of gold is half as much again as that of 

 platinum. If, however, we compare gold and copper, which 

 occupy parallel positions in Mendel6eff's scheme, we see 

 that they are very much alike, and the same holds with 

 regard to magnesium and mercury, which occupy a homo- 

 logous position. If these facts indicate anything more 

 general, we should e.xpect the metals of the palladium and 

 iron group to have a low compressibility like platinum, 

 zinc and cadmium to have a very high compressibility like 

 magnesium, and thalliuin an intermediate but still consider- 

 able compressibility like aluminium. 



It will be observed that the two kinds of glass mentioned 

 in Table I. are more compressible the greater their 

 density. This may, however, be due to a specific feature of 

 the o.xide of lead which enters largely into the composition 

 of the flint glass. 



Referring to the use of glass exposed to high internal 

 pressure, the author says : — In the work connected with this 

 paper, which extended over the greater part of four weeks, 

 fifteen glass terminals gave way, and oddly enough, the 

 failures were as nearly as possible equally distributed 

 between the two ends ; eight of them fell to the left arm 

 and seven of them to the right arm. The bursting of a 

 terminal causes no inconvenience beyond the trouble of re- 

 placing it, because the construction of the instrument enables 

 air to be completely excluded from it, and the quantity of 

 water in it to be kept within such limits that its resilience 

 is of no account. When a tube bursts it usually splits 

 longitudinally up the middle into two slabs. One of these 

 almost always remains entire ; the other is sometimes broken 

 into, fragments, but there is never any projection of material 

 unless, the instrument has been carelessly put together and 

 air admitted. The paper concludes with an account and 

 an illustration of some curious microseismic effects produced 

 on the wires by the explosion of the glass terminals. 



Geological Society, April 13. — Dr. J. E. Marr, F.R.S., 

 president, in the chair. — The discovery of human remains 

 under the stalagmite-floor of Gough's Cavern, near 

 Cheddar : H. N. Davies. Gough's Cavern opens at the 

 base of the clilTs on the south of Cheddar Gorge. Human 

 and animal remains have been discovered at ditTerent times. 



NO. 1802, VOL. 70] 



The principal deposits are a stalagmite-like travertine over- 

 lying cave-earth. When excavating part of a fissure 

 running northward a human skeleton was discovered, 

 associated with flakes, scrapers, and borers of flint, em- 

 bedded in cave-earth. The remains of the skeleton 

 excavated comprise the skull, the bones of an arm, a leg, 

 and part of the pelvic girdle. The other bones were allowed ■ 

 to remain in situ, and may now be seen. The position of 

 the skeleton was that which would have been assumed by 

 a drowned man. Interment is unlikely, because of the 

 shape of the fissure, which was choked up with di5bris and 

 calcareous deposits. The stature of the man was 5 feet 

 5 inches ; he was of muscular build, with prognathous jaws, 

 a straight thigh, a platycnemic tibia, and a thick dolicho- 

 cephalic skull. The animal remains found in the cave- 

 earth of other parts of the cavern are those of mid- and 

 late Pleistocene age, and this evidence, together with that 

 derived from the position and character of the skeleton, 

 and the workmanship of the flakes, points to a period 

 towards the close of the Palaeolithic or the opening of the 

 Neolithic age. — History of volcanic action in the Phlegra?an 

 I'ields : Prof. Giuseppe De Lorenzo. The author 

 recognises three chief periods in the volcanic history of the 

 district : — (i) The eruptions which took place under the sea 

 during the Pleistocene period. Their surviving products 

 can be grouped in two divisions. The older of these 

 (a) is represented by the piperno and grey pipernoid tuffs 

 of the Campania. These deposits consist of grey trachytic 

 tuff, with scattered black scoriae, and with a varying pro- 

 portion of non-volcanic sediment. The vents whence they 

 were ejected are now no longer to be traced. The author 

 is disposed to regard the piperno as a trachytic lava with 

 schlieren, the dark lenticles being made up of such minerals 

 as augite, aDgirine, and magnetite, while the lighter matrix 

 is felspathic (anorthose) with a spherulitic structure and 

 inicroliths of aegirine and augite. The second phase (h) of 

 the first eruptive period is represented by ashes, lapilli, 

 pumice, and sands, intercalated with marine shell-bearing 

 clays and marls, and also with conglomerates and breccias. 

 (2) Above the records of the first volcanic period lie those 

 of the second — the yellow tuff, which forms the most 

 characteristic of the volcanic formations of the Phlegraean 

 Fields. It is a yellow, compact, well stratified aggregate 

 of trachytic detritus, through which are scattered fragments 

 of tuff and lava. Its average thickness exceeds 300 feet. 

 It was a submarine accumulation. Owing to the uniformity 

 of its lithological characters, this tuff has not furnished 

 evidence of a definite order of succession in the eruptions 

 to which it was due. It is possible to recognise vents from 

 which the tuff was discharged. (3) After the discharge of 

 the yellow tuff the volcanic tract appears to have been 

 upraised into land, and to have been exposed to a period of 

 subaerial denudation. \'ents made their appearance and 

 discharged fragmental materials, differing from the tuff in 

 showing a greater variety of composition, and in the proofs 

 which they furnish of a succession of eruptions, and a 

 gradual southward shifting and diminution of the eruptive 

 energy. The largest and most ancient of the volcanoes of 

 this latest period is that of Agnano. Not improbably it was 

 from this eruptive centre that the trachy-andesitic lava of 

 Caprara issued. The crater-lake of Avernus belongs to the 

 latest group, and perhaps it was the water percolating from 

 this basin to the thermal springs of Tripergole which, in 

 September, 1538, gave rise to the explosion that built up 

 Monte Nuovo — the youngest of the cones of the Phlegnan 

 Fields. 



Entomological Society, April 20. — Dr. F. A. Dixey, 

 vice-president, in the chair. — Mr. M. Jacoby exhibited a 

 (^ specimen of the beetle Sagra seiiegalciisis with 9 

 characters, received from Mr. Barker in Natal. — Dr. 

 Norman Joy exhibited Orochares angiistata, Ev., taken at 

 Bradfield, Berks., in December, 1903 — the second recorded 

 British specimen ; a species of Tychius, which he said might 

 be a variety of Tychius polylincatus. Germ, (not now in- 

 cluded in the British list), or, more probably, a new species 

 closely allied to it, taken near Streatley, Berks., last year; 

 and two specimens of Psclaphus dresdciisis, Herbst., taken 

 near Newbury this year. — Mr. C. O. Waterhouse exhibited 

 an unnamed species of Nemoptera from Asia Minor, re- 

 sembling Ncmopterii huttii from .Australia. — Mr. F. Enock 



