OcTOBER 2, 1902 | 
NATURE 
955 
(May 12) after eleven o’clock we had a slight horizontal 
trembling movement from a south-westerly direction.” 
AN aérial luggage transmitter has been erected recently by 
the L. and S.W. Railway Company at their junction at Woking, 
and is, we understand, in the nature of an experiment, being, it 
is believed, the first appliance of its kind used by any rail- 
way company in the kingdom. In briefly describing it, 
Engineering states that on the up and down platforms are erected 
iron towers, each 32 feet 6 inches in height, and set in blocks 
of concrete. Suspended from tower to tower are four spans of 
wire cable. The topmost cable, on which the transmitter runs 
to and fro, is exceptionally strong, and is capable of bearing a 
strain equal to at least 20 tons. The second cable keeps the 
transmitter in position, and the third and fourth cables, which 
are much thinner and are in one length, are for ‘‘ paying out ” and 
“returning.” Each span is rio feet long, and the height of the 
transmitter above the railway is 22 feet 6 inches. Attached to 
the transmitter is an iron cage capable of holding half a ton at 
one time. The wholeis worked by hydraulic power, the engine 
being on the down side. Above it is a small box in which are 
the levers working the apparatus. The transmitter is very rapid in 
its working, taking only 30 seconds to deposit 10 cwt. of luggage 
from one platform to the other. All the experimental trials 
have been, it is said, most satisfactory, and the transmitter is 
now ready for use. 
ATTENTION has recently been called to the possibilities of the 
balata fields on the Amazon. A gutta-percha merchant in the 
Guianas, examining this region about a year ago, found the 
balata tree growing in abundance near Para, and on the Amazon 
and its tributaries for thousands of miles. The Brazilians had no 
knowledge of its gum-producing qualities, and were found 
cutting down the trees for firewood and building material. A 
concession was bought, and the practical work of producing 
gutta-percha for the market begun. As in the case of 
rubber, there is practically no limit to the supply of gutta-percha 
on the Amazon, and, as it can be produced at a fraction of the 
cost of rubber, it offers a much higher percentage of profit. 
The method of bleeding the balata tree is entirely different from 
that used to extract the gum of the rubber tree, and only 
experienced and expert bleeders can be employed. But, on the 
other hand, these trees yield many times as much sap as the 
rubber trees, and one man can, it is said, easily produce as 
many kilograms of gutta-percha in a day as twenty men can 
extract of rubber. Each tree will average 34 Ib. of gutta- 
percha and a competent bleeder can prepare 4o to 50 Ib. 
per day. The gum is first fermented and then dried in the sun, 
after which it is ready for shipment. 
WE have received several communications on the variation 
of the smallcopper but terfly (Ci7ysophanus Phlaeas, Linn.) with 
reference to the letter of a correspondent in our issue of Sep- 
tember 11. The insect is very variable, and the row of blue spots 
inside the dark border of the hind wing, which has been specially 
referred to, is not uncommon, and according to Riihl (‘‘ Palceark- 
tischen Grossschmetterlinge,”’ i. p. 217) is only met with in the 
female. The insect extends throughout the whole northern hemi- 
sphere, and exhibits local variation in many parts of its range. 
In the south of Europe and Asia, a larger and darker variety, 
with rudimentary tails (var. Z/ezs, Fabricius), is not uncommon. 
The species is also very prone to albinism, specimens 
with the usual copper colour of the wings replaced by white, 
leaving only the black markings dark, being occasionally met 
with (var. Schmidtzz, Gerhard). We are not aware that it ever 
hybridises with ‘‘ blues,” as one of our correspondents has sug- 
gested. We may refer readers who require further information to 
the following works :—Barrett’s ‘‘ Lepidoptera of the British 
Islands,” vol. i. pp. 62-65, plate 2, Figs. 2, 2a to 27 (Fig. 2a 
NO. 1718, VOL. 66] 
represents the white form); Tutt’s ‘‘ British Butterflies,” 
pp: 152-155; Mosley’s ‘‘ Illustrations of Varieties of British 
Lepidoptera,” part 10 (‘t Polyommatus Phlzeas”’), plates 1 and 2 
(twelve varieties figured, some very remarkable, including not 
only coppery and black and white forms, but a dark greyish 
brown specimen, slightly suffused with copper and marked with 
a few large black spots); Riihl’s ‘‘ Palzarktischen Gross- 
schmetterlinge,” Band 1, pp. 217, 218, 746, 747 (this work 
gives full information respecting the foreign range and variation 
of the insect) ; Staudinger and Rebel, ‘‘ Catalog der Lepidopteren 
des Palzarctischen Faunengebietes,” p. 74. Mr. F. Merrifield 
has also called our attention to his paper on ‘‘ The Coloration 
of Chrysophanus Phiaeas as affected by Temperature,” in the 
Entomologist for November, 1893 (vol. xxvi. pp. 333-337)- 
THE report on ‘‘ British Rainfall for the Year 1901,” com- 
piled by Mr. H. S. Wallis and Dr. H. R. Mill (60 + 252 pp. 
large 8vo), contains, as usual, most valuable and trustworthy data, 
showing the annual distribution of rain over the British Isles, as 
observed at about 3500 stations, together with the number of 
days on which 001 inch or more fell. This most useful organ- 
isation is so well known that it seems scarcely necessary to refer 
to the articles which regularly appear upon various branches of 
rainfall work. The notes on the meteorology of the year and 
on the principal phenomena, arranged according to months, are 
exceedingly interesting and valuable for reference, as are also the 
tables showing the heavy falls in short periods and the monthly 
rainfall at 232 stations. The comparison of the rainfall of the 
year with a thirty years’ average is very instructive, and shows 
at a glance that, on the whole, there has been a great de- 
ficiency in the total amount. In the eastern counties the 
deficiency reached 30 or 35 per cent. of the normal value. 
In the Zransactions of the South African Philosophical Society 
of June last, Mr. J. R. Sutton contributes an elaborate 
paper on the ‘‘ Pressure and Temperature Results for the Great 
Plateau of South Africa,” accompanied by useful daily and 
monthly means for the years 1888-97. The discussion exhibits 
a systematic comparison between the temperatures and pressures 
of the air over a plateau and corresponding coast station, as 
represented by observations at Kimberley and Durban, similarly 
lo comparisons between the summit and base of a mountain. 
THE United States Weather Bureau has published a valuable 
memoir on West Indian hurricanes (Bx //etin No. 32), prepared 
by Mr. W. H. Alexander from all available sources. Part of the 
information has been published in a previous Az//etin, but the 
present paper includes additional observations on those of 
St. Kitts and Porto Rico in particular, with brief historical 
notes of the most remarkable storms that have occurred from 
the earliest times. 
THE Journal of the College of Science of Tokio (vol. xvi. 
article 7) contains an interesting paper entitled ‘‘ Studies in 
Atmospheric - Electricity,” by Prof. Y. Homma. The facts 
discussed have been obtained chiefly from observations and 
documents belonging to the Central Meteorological Observatory 
of Japan. The principal conclusions are :—(1) The negative 
potential observed during strong wind is entirely due to the 
negative electrification of the dust in the atmosphere by friction 
with terrestial objects ; (2) similarly the high potential observed - 
during fog or haze is due to the positive electrification of the 
water particles composing it ; (3) when a mass of cold air comes 
in contact with a mass of warm air, the former becomes positively 
electrified with respect to the latter; (4) the high potentials 
about sunrise are probably owing to the air near the surface 
having a lower temperature than the air above it, and becoming, 
in consequence, positively electrified ; (5) when two masses of 
air at different temperatures happen to be mixed suddenly, the 
