Ferruary 28, 1907 | 
NATURE 
423 
Part i. of vol. xxvii. of the Transactions of the South 
African Philosophical Society is devoted to the description 
by Mr. R. Bergh, of Copenhagen, of a collection of South 
African opisthobrahchiate molluscs. Hitherto the known 
South African representatives of this group have been very 
few, but Mr. Bergh has been able to describe quite a 
number of new many referable. to the 
Aplysia.. Owing largely to the influence of currents, there 
is a marked difference between the marine faunas of the 
west and east sides of the Cape Peninsula, the latter 
having a more tropical Indian character. Still, however, 
typical forms of nudibranchs do occur on the west side. 
The collection is due to the energy of Dr. Gilchrist, after 
whom one of the species of Aplysia is named. 
species, genus 
We have received copies of three papers dealing with 
injurious insects recently issued by the U.S. Department 
of Agriculture. In the first of these, forming Farmers’ 
Bulletin No. 275, Mr. L. O. Howard discusses the gipsy- 
moth (Porthetria dispar) and the means by which it can 
best be kept under control. This moth, we may remind 
our readers, is a European species, accidentally introduced 
into Massachusetts some forty years ago, since which 
date it has spread to Rhode Island, and parts of New 
Hampshire, Connecticut, and Maine. For a long time 
Massachusetts was left to fight the battle against the in- 
vader alone, but the Federal Government has at length 
recognised its duty of contributing to the expenses of the 
campaign. Of the other two papers, forming parts i. and 
vi. of Bulletin No. 63 of the Bureau of Entomology, one 
is devoted to the hibernation and development of the 
cotton-boll weevil, and the other to its ally, the strawberry 
weevil. It has been stated that the best method of de- 
stroying the first-named species is by burning or grazing 
off the cotton stalks in early autumn, so as to reduce by 
starvation the numbers which hibernate. As a large per- 
centage die during hibernation, this plan is obviously much 
more efficacious than are attempts at destruction in spring. 
The strawberry weevil in 1905 inflicted damage on crops 
in Texas averaging about 12-5 per cent. 
Or all the statistical reports annually published in the 
volume on the mineral resources of the United: States, 
issued by the U.S. Geological Survey, none is of greater 
interest than that dealing with the production of precious 
stones; and the report for 1905, an advance copy of which 
we have received from the author, Dr. George F. Kunz, 
well maintains the high standard set by preceding reports. 
It deals not only with the production of precious stones 
in the United States, but also with the occurrence and 
production of precious stones in other parts of the world. 
In the United States the year 1905 was a memorable one, 
as it marked a record for the importation of precious 
stones of every variety. The value of diamonds and other 
precious stones amounted to little short of 7,000,000l., 
while the value of the production of precious stones in the 
United States was 65,2501. 
green variscite (aluminium phosphate), a translucent green 
stone used as a gem, at a new locality, forty miles south- 
west of Salt Lake City, promises to furnish a quantity 
of this peculiarly American stone that may be used in 
semi-barbaric jewellery. In the mining of tourmaline, 
beryl, topaz, kunzite, and other stones peculiar to the 
southern counties of California, some wonderful crystals 
of rose-coloured beryl! implanted on felspar and many fine 
crystals of red and green tourmaline are found, and in 
connection with them occur many specimens of great 
mineralogical interest. The region bids fair to excel that 
No. 1948, VOL. 75] 
The discovery of utahlite, a 
of the Ural, which for more than half a century has led 
the world in such products. A novel departure has been 
the cutting of the chrysoprase found at Visalia, Cali- 
fornia, in its brown matrix, which forms a pleasing con- 
trast to the green colour of the gem. The emerald is still 
the stone most prized, and at no time has it received so 
high appreciation in price. Within the last two years 
there has been immense improvement in lapidary work 
in the United States in every variety of stone. There has 
been especial preference for many of the larger stones, 
and have tourmalines, and 
amethysts been sold in such profusion. 
never before aquamarines, 
In the Bulletin de la Classe des Sciences (Brussels) 
M. P. De Heen publishes a photograph, taken in the Place 
Saint Lambert during a thunderstorm, showing remark- 
able luminous effects emanating from each of the electric 
arc lamps at the instant of a flash of lightning. These 
effects consist partly of bands of light passing from the 
lamps to the ground, which the author thinks may be 
caused by conduction currents, but in addition they include 
two luminous filaments emanating from each lamp, one 
forming a closed curve and the other curling round at its 
extremity in the form of a lasso. M. De Heen expresses 
the opinion that these effects have their seat in the ether, 
and cannot be accounted for by any corpuscular (or elec- 
tron) theory of electricity; but whatever may be said on 
this point, the discharges in question appear to be well 
worth careful study. 
In the British Journal of Photography for February 15 
there is an article entitled ‘‘ British Plates in Germany,”’ 
in which the writer refers to the great outcry against the 
increasing imports of English plates into Germany. The 
reader will gather some idea of this great invasion of 
British-made plates from the following statistics (in kilos.) 
which are given :— 
1903 1904 1995 1996 
9600 23,300 38,700 83,000 
The above figures show that, as the writer states, ‘* in 
open markets the British dry plate has held its own 
against all comers, and has now shown its capability of 
disturbing the ranks of manufacturers in a country where 
home production is favoured and foreign competition handi- 
capped by a tariff... The tremendous increase from the 
year 1905 to 1906 has been referred to in a German photo- 
graphic journal as ‘‘ gefahrvoll fir die deutsche Industrie,” 
and German plate makers are now taking a serious view 
of the situation. The writer tells us that the cry is raised 
of German-made glass for the German plate maker, be- 
cause at the present time the latter has to import his 
glass from Belgium or Great Britain, and “ to pay on it 
pretty nearly as much duty as is paid by the importer of 
the English plates.’’ A practical illustration of the situ- 
ation is summed up by the writer, who narrates that when 
paying a visit to a large German polytechnic, in the in- 
struction rooms he found students being shown the making 
“Thomas’s ’’ plates, and of 
tissue. 
of positive transparencies on 
carbon prints on ‘‘ Autotype ”’ 
Tue recent public inquiry at Dunfermline with reference 
to the death of a miner by an electric shock caused by 
a haulage rope being made alive, directs attention to the 
very unsatisfactory state of affairs which still exists in 
a large proportion of our collieries. It is lamentable that 
the present calamity and many previous cases were due to 
the fact that men who have not been technically trained in 
electrical work are placed in charge of electrical machinery, 
and although they may be quite practical engineers from 
