SEPTEMBER 4, 1902] 
MAT ORE 
441 
If the earth movement took place at the Cape as an absolutely 
perpendicular vibration, would the seismograph have recorded 
it? 
Can sudden and abnormal change in atmospheric pressure 
cause volcanic or other disturbance on the earth ? 
August 19. F. C. CONSTABLE. 
In Nature, August 14, p. 371, it is stated that ‘‘at 7 o’clock 
on the morning of May 8, Mr. Ferdinand Clerc observed the 
needle of a large aneroid barometer pulsating violently.” Above 
this there is, however, another note which says that ‘‘ nothing 
unusual was observed in the barometer.” But even supposing 
barometric perturbations to have taken place on May 8 in 
St. Pierre, what connection could these have had with pheno- 
mena which happened twenty days later at the Cape of Good 
Hope ? 
The Milne horizontal pendulum installed at this latter place 
will record disturbances originating at its antipodes, but will 
not respond to the rapid elastic vibrations of localshocks. You 
may hear seismic sounds, windows and doors may rattle, but 
the instrument in question will remain at rest. 
The movement of an earth particle at the time of an earth- 
quake is in all azimuths and at varying angles with the horizon. 
A strictly perpendicular movement seems an impossibility. 
Abnormal changes in atmospheric pressure may act on a 
region in a state of excessive seismic or volcanic strain much in 
the same way as the last straw is said to 
act upon the camel’s back; the relation- 
ship, however, is far from being pronounced. 
This and other questions referred to by 
Mr. Constable are discussed in the volumes 
on ‘‘Seismology” and ‘‘ Earthquakes” 
published in the International Scientific 
Series. J. M. 
August 26. 
Larva Stage of Heliocopris 
Isidis. 
In the month of March last, I discovered 
at a depth of a few cm., among the roots of 
the tree Albz227a Jebbek, several large balls 
of earth, varying in diameter from 5’0 to 
85cm. These on being broken open were 
found to be hollow spheres, the thickness 
of the wall being about 1°5 cm. This wall 
was composed of concentric layers of mud 
and bits of vegetable matter mixed, having 
the composition and appearance of native 
unburnt bricks. 
Inside the sphere was a coleopterous 
larva about 2°0 cm. in diameter at its 
thickest part, about 9°0 cm. in length 
measured along the dorsal line, and about half that length 
measured along the ventral line ; the larva lay on its side and 
assumed a curved position. A few days ago, an imago of 
Heliocopris (sidis emerged from one of the balls by boring a 
hole in the roof of its cell just large enough for it to pass 
through. 
If any of these facts are new in the life-history of this beetle, 
they might interest your readers. FRED. FLETCHER. 
School of Agriculture, Ghizeh, Egypt, August 14. 
THE LAVA-LAKE OF KILAUEA. 
HE recent destructive eruption in Martinique has 
revived interest in the question of the causes of 
volcanic action. Only lately have I become sensible of 
the peculiar value of some observations of my own as 
evidence of the fvzmary force which impels the ascent 
of lava from its interior habitat, as distinguished from 
the explosive violence caused by steam generated by the 
encounter of the ascending lava with ocean and other 
surface waters. 
I have long believed the primary force to reside in 
the expansion of the gases originally occluded in the 
magma, ever since its first condensation from the nebula. 
NO. 1714, VOL. 66] 
Whenever released from solidifying pressure by disturb- 
ances of the superincumbent crust, the intensely hot 
magma bursts into a viscid foam and pushes upwards. 
In a quiet volcano like our Kilauea, meeting no water to 
generate explosive steam, the lava wells up continuously 
and steadily in a comparatively gentle fountain, which 
displays effervescence only on the surface. 
In support of this opinion I beg to offer positive evi- 
dence contained in certain facts observed by myself in 
Kilauea during April 8-14, 1892, and on August 28, 
1894. The volcano had been in very steady and uniform 
action for nearly two years before the earlier date, and so 
continued until a short time after the latter date, or nearly 
five years in all of a quiet, continuous and rather copious 
welling up of lava, wholly unattended by any explosive 
action. 
_ On the earlier date I carefully observed the then exist- 
ing lava-lake during six successive days. This lake 
occupied the centre of the inner crater, called Hale-a- 
mau-mau, or Fern-hut. The main crater called 
Kilauea is nine miles in circumference, averaging 400 
feet in depth, and rather unevenly floored with recent 
lava. South-west of the centre is the inner pit of 
Hale-a-mau-mau. This pit was at that time nearly circular 
Fic. 1.—Fire-lake as seen in 1891-2. 
and 2400 feet in diameter, with vertical sides averaging 
150 feet down to the talus. Before the welling up of 
lava began in 1890, the pit had been about 700 feet deep. 
In two years the lava had risen 4oo feet, and stood 
within 300 feet of the rim and main floor. 
A lake of liquid lava, covered by a thin, spongy film, 
occupied the centre of the pit. This lake was nearly 
circular, averaging 850 feet indiameter. It was bordered 
by a low dyke, which partially restrained its frequent 
overflows. Outside of the dyke, freshly congealed lava 
sloped away to the talus. By day the crust-film was 
grey to the eye, but by night adeep red. It was traversed 
by numerous fissures of white fire. During the whole 
time three fountains of lava were welling up with some- 
what regular intermittence, and three smaller ones at 
irregular intervals. There was no explosive action 
whatever. 
The largest fountain was about 120 feet south-east of 
the centre of the lake. It played with great regularity 
about three times in a minute, rising ina round billow 
25 feet high and 50 feet in diameter, bursting at the top 
and falling back to level, its discharge moving ina broad 
stream towards the centre of the lake. The fling of 
spray from its summit rose to 4o or 50 feet above the 
level. 
