May 1, 1902] 
NATURE 
15 
Hospital. The exhibition will be opened on August 29, and 
intending exhibitors should communicate as soon as possible 
with Herr Pasche, Réntgen Institute am Inselspital, Bern. 
Ar the present time, when much attention is being given to 
the reform of mathematical teaching associated with the name 
of Prof. Perry, the pamphlet entitled ‘‘The Cultivation of the 
Mathematical Imagination,’ by Miss Mary Everest Boole 
(Colchester: Benham and Co., price 6¢.), appears very oppor- 
tunely. The methods advocated by the authoress belong chiefly 
to the kindergarten stage of education, but there are many 
suggestions that are appropriate to a slightly more advanced 
stage ; the central idea is always that of leading up to general 
truths by means of concrete processes. The pamphlet should 
be very helpful to teachers who wish to find out how to prepare 
the minds of young children to receive formal mathematical 
instruction. 
Pror. R. W. Woop writes :—‘‘It may perhaps be a matter 
of some interest to teachers whose laboratory facilities are 
limited to know that solid carbon dioxide can be obtained 
from the sparklets now sold everywhere for a penny or two for 
the aération of beverages. The larger of the two sizes gives 
the best yield, of course. It is best to cool the sparklet in ice 
and salt for a few minutes before the experiment, and doubtless 
the amount of solid obtained would be still further increased by 
chilling the metal reservoir with which the bottles are fitted. 
A small square of black velvet should be held, or tied with a 
turn or two of string, over the end of the tube which delivers 
the :gas into the fluid. The nap of the cloth should be on the 
inside, and the part over the tube should form a little bag about 
the size of a marble. On discharging the sparklet and quickly 
removing the bag, the interior will be found to be lined with the 
snow-white solid, with which a small drop of mercury can be 
easily frozen. The substance shows off most beautifully on the 
jet black surface of the velvet.” 
THE death is announced of Mr. William Henry Penning. 
After pursuing a course of engineering under Mr. C. H. 
Gregory, he joined the staff of the Geological Survey in 1867 
and was engaged in mapping portions of Essex, Suffolk, Cam- 
bridgshire and Lincolnshire. He was joint author of memoirs 
on the geology of the neighbourhood of Cambridge, Lincoln, 
and parts of Essex. He was author also of ‘* A Text-Book of 
Field Geology,” 1876 (edit. 2, 1879), and of ‘‘ Engineering 
Geology,” 1880. In 1882, through ill-health, he resigned his 
post on the Geological Survey and spent some time in South 
Africa. He died on April 20. We have also to regret the 
death of Mr. Joseph Nolan, who joined the Geological 
Survey in Ireland under Jukes in 1867, and after many years of 
active service in the field became in 1890 resident geologist 
in the Dublin office. He was author or part author of several 
memoirs in explanation of the Geological Survey maps. He 
retired from the public service in 1901 and died on April 19. 
A STRONG earthquake was felt round Lake Baikal on April 12. 
{t began at Irkutsk bya severe shock at 6h. 40m, a.m., the pen- 
dulum of the observatory being deflected by 22 mm. About twenty 
fairly severe shocks followed during the first minute. Groups of 
shocks next occurred, the strongest of them being at 7h. 13m., 
7h. 31m., 7h. 36m. and 8h. t4m. All these shocks could be 
felt even without instruments, their force attaining the value of 
5 in the seismic scale. The earthquake was widely felt round 
Lake Baikal. At Selenghinsk the chief disturbance travelled 
in a direction from S.W. to N.E. and the following shocks 
were noticed :—at 7h. om., 7h. 50m., 7h. 54m. and 8h. 35m. 
At the village Snyezhnaya, on the eastern coast of the lake, 
several chimneys were destroyed and crockery was thrown down. 
Further east, at Verkhneudinsk, and on the western coast, 
NO. 1696, VoL. 66] 
the shock was much feebler. During the night of April ro-11 
a very strong earthquake was felt in the north of Finland. At 
Uleaborg window panes rattled and crockery fell from its place. 
Shocks of earthquake continue also to be felt at Shemakha. 
Two severe shocks were noticed on April 17 at 1oh. om. and 
Ioh. 30m. p.m. 
Ir seems at first sight to be a bold statement to put forward 
that the study of the distribution of plants may be dated back 
to the time of Alexander the Great. But no more weighty 
opinion could be obtained than that of a scholar who has com- 
bined the study of classics and botany. Herr Hugo Bretzl, asa 
thesis for his doctorate in Strassburg, has made a careful study of 
Theophrast’s ‘‘ Plant-geography,” and comes to the conclusion 
that from the description there given of the air-roots of A%czs 
bengalensts the writer must have been able to refer to the original 
accounts of Alexander’s expedition. The brochure received 
gives two chapters from the whole work, which is to be pub- 
lished in book form and promises to be exceedingly interesting. 
Not only does the author show that the Greeks realised such 
facts as the absence of the pine in all the countries which inter- 
vene between Macedonia and India, but incidentally his refer- 
ences suggest that the Aristotelan writers have not received 
due justice at the hands of other writers of historical botany. 
Ir will be remembered that in a recent issue notes of the 
discovery of a blood parasite occurring in man and belonging to 
the genus Trypanosoma were recorded. The case was one of a 
European, whose chief symptoms were irregular rises of temper- 
ture with afebrile intervals, the attack being accompanied by 
increased frequency of respiration and pulse. The parasite 
was present only during the febrile attacks, and whilst it 
closely resembled Z. Avucez in form and staining reactions, it 
was, however, considerably smaller and in fixed specimens 
assumed a characteristic ‘‘set.” Another striking feature, 
which reminds one of the diseases known as Nagana and Surra 
in horses and cattle, is the occurrence of cedema of the eyelids 
and feet. Nepveu claims to have discovered this parasite in 
man in Algiers, but his description is very imperfect and raises 
considerable doubts as to whether what he saw were really 
trypanosomes. Mr. J. Everett Dutton, who described the parasite 
occurring in the blood of a European at Bathurst, West Africa, 
has within the last few days added the most interesting obser- 
vation that the parasite occurs also in native children. Whilst 
examining for malaria parasites a large number of microscopical 
blood preparations of the native children of a small village, a 
few miles nearer the mouth of the River Gambia than Bathurst, 
he found in one preparation a number of trypanosomes resem- 
bling in every way those found in the case of the European 
before recorded. This second observation opens up a_ large 
field for further investigation and points to the extreme im- 
portance of the study of the diseases of natives, especially from 
a parasitological point of view, in West Africa and other parts 
of the world. 
THE Meteorological Office Pilot Chart for May gives a short 
account of submarine earthquakes and the curious sensations 
they produce on board ship. Within the basin of the North 
Atlantic the fairly well-defined seismic regions are near the 
equator, between 19° and 33° W. ; about the West Indies ; from 
the Cape Verde Islands north-westward to about 33° N., 41° 
W. ; and from 34° to 45° N., 13° to 30° W. The ice season 
this spring is very late, no bergs having been reported down to 
April 16. The St. Lawrence River was open for navigation at 
Quebec on April 3, an unusually early date. Numerous obser- 
vations show that during the month of February last the 
temperature of the surface water of the Atlantic was below the 
average over a space extending south-westward from the British 
