SEPTEMBER 18, 1902] 
NATURE 
ous 
relations between the mouth-organs of diptera and those of 
other insects. Even in such dipterous genera as Tabanus and 
Culex, the full number of mouth parts of a typical insect is not 
present, the absent parts being one pair of palpi, which are com- 
monly regarded as the labial palpi. In other families, such as 
the Muscidee and Syrphide, where mandibles and even maxillze 
are absent, chitinous structures are visible on the dorsal side of 
the labium representing the aborted parts. Mr. Wesché now 
finds that certain members of the Muscidee are provided with a 
second pair of palpi in addition to those always present and 
which are generally regarded as maxillary. ‘‘ In several species 
of the Anthomyia family, in the genera Hyetodesia, Spilogaster 
and Hydrotea, are to be found at the base of the labium and 
hypopharynx, and connected with the apodemes or levers that 
work those parts, two hairy processes, one on each apodeme. 
These are jointless, chitinous in structure, and have much the 
appearance of ordinary palpi.” In Hyetodesta basalis, the 
organs measure about 0°003 inch (0°085 mm.) in length, while 
in Sprlogaster duplicata they are the same length and about half 
the breadth. In other species of the same family, the rudiments 
are reduced to a few hairs anda minute tubercle ; in the Sarco- 
phagidee, rudiments are found in AZyiocera carinifrons ; in the 
Muscide proper in Musca corvina and M. domestzca, and the 
palpi have also been found in the families Sepsidze, Opomyzidze 
and Borboridz. The discovery of these rudimentary palpi, 
which are undoubtedly maxillary, leads to the conclusion that 
the palpi so conspicuous on the proboscis of many flies are not 
the maxillary but the labial palpi. 
EIGHT years ago Prof. Omori studied the distribution in time 
of the after-shocks of several great Japanese earthquakes, and 
concluded that a strong earthquake is almost invariably followed 
by weaker ones, and a destructive one by hundreds or even 
thousands of minor shocks, which gradually diminish in fre- 
quency and strength, but may continue to be felt for several 
years. In a recent valuable memoir (So//. Soc. Sism. Ttal., 
vol. vili. pp. 17-48), Dr. Cancani has investigated the distribu- 
tion in intensity of the after-shocks of three hundred Italian 
earthquakes, all strong enough to produce at least slight damage 
in buildings. Such earthquakes, he finds, are never isolated, 
but are always preceded or followed by others generally weaker. 
The total duration of an earthquake-period (perhaps earthquake- 
series or group would be a better term) is a function of several 
variables, but depends especially on the depth of the seismic 
focus. When the depth is small, the earthquake-period is of 
brief duration, generally about ten days ; when moderate, the 
after-shocks may continue for about three months, and when 
the depth is great they may last for several years. In 70 per 
cent. of the earthquake-periods, the strongest shock occurred 
during the initial phase or first tenth part of its total duration. 
Tue Report of the Botanical Exchange Club of the British 
Isles for 1901 has been delayed, as the distributor, the Rev. E. S. 
Marshall, explains, in order to obtain critical opinions on some of 
the specimens. The number of specimens sent in by twenty- 
five contributors amounts to more than 2700, Many of these 
are varieties or hybrids, others represent new localities. Several 
new species are recorded for Lancashire, notably Hed/eborus 
viridis and Helleborus foetidus, Scirpus caricis and Carex 
teretriuscula. A discovery of Euphorbia exigua in limestone 
crevices on the north coast of Wales lends support to the view 
that it is a native of Britain. Statice Limondum x rariflora 
and Salicornia lignosa, both growing near Bosham in west 
Sussex, have elicited interesting criticisms, but the most im- 
portant collection, Dzotrs candidissima, was made by Mr. C. P. 
Hurst in Wexford. There it grows in quantity on a sandy bar, 
as may be seen from the: two illustrations given, which are 
reproduced from photographs taken by the finder. 
HOw DeeGmo’,. 661) 
A NUMBER of papers dealing with electric traction, which 
were read before the Association Francaise pour l’Avancement 
des Sciences last month, are summarised in Z’£clairage 
electrigue for August 23. These will be found especially 
useful by those who are interested in accumulator traction, 
whether for tramways or automobiles, as the suitability of the 
accumulator is considered from several points of view. The 
general conclusions are not very favourable to the accumulator in 
its present commercial form, although accumulator traction was 
voted a perfectly practical solution of the problem of running a 
tramway electrically in a position in which trolley wires were 
inadmissible. Accumulators were not, however, regarded as so 
suitable for automobiles, as their weight involved difficulties in 
the construction of the cars and tyres which were not so im- 
portant in a tramcar heavy in itself and running on a prepared 
track. For a public service of electric automobiles, the only system 
considered practical was one in which power was obtained from 
a trolley wire, with omnibuses or carriages running on the 
ordinary roadway, a system which obviously possesses some 
advantages over even the electric tramway. 
A BRIEF account of the latest apparatus for rendering air 
respirable in a closed space is described by M. Desgrez in the 
Bulletin of the French Physical Society, No. 185, the apparatus 
having been devised by M. Desgrez in collaboration with M. 
Balthazard. The underlying principle is the decomposition by 
water of sodium peroxide, with liberation of oxygen, absorption 
of carbon dioxide and destruction of the toxic products of 
respiration. The apparatus consists of (1) a distributor which, 
by the action of clockwork, drops the peroxide into water at 
regular intervals ; (2) a cubical steel box containing the water ; 
and.(3) a ventilating fan. A refrigerator is also supplied, as a 
general rule, to counteract the heating effects of the chemical 
reactions. A complete apparatus has been constructed, capable 
of enabling a man to work for at least three-quarters of an hour 
in a closed space, and wéighing in all about 12 kilograms. 
THE current number of the Proceedings of the Edinburgh 
Mathematical Society contains a note on decimal coinage and 
approximations by Mr. J. W. Butters. Apart from the ad- 
vantages of a decimal system of coinage, the author calls attention 
to several points which cannot be too strongly emphasised. One 
is the common complaint as to the time wasted by learners in 
using long and cumbersome methods (often calculating sums of 
money to a fraction of a penny with a long numerator and 
denominator), from ignorance of the use of decimals. This 
evil, the author thinks, could be remedied by teaching decimals 
before vulgar fractions, as is often done in Germany. Another 
point is the use of the unit’s figure instead of the decimal point 
as a landmark in counting places in multiplication and 
division. Everyone knows, or should know, that the charac- 
teristic of a logarithm is given by the number of places that its 
first significant figure is to the left of the unit’s figure, whereas 
if the decimal point is taken as the landmark, we are told 
that the characteristic is one more or one less than something 
or other and confusion may arise. Mr. Butters suggests that 
the decimal point be called the unit’s point and regarded as 
used for fixing the unit’s place, and he shows how multiplica- 
tion and division of decimals are simplified by adopting this 
view. The necessity for such a change is emphasised by the 
fact that the ordinary method of dividing decimals fails to give the 
correct remainder. Finally, the author points out the saving 
in labour in using decimals of a pound and contracted methods 
for ordinary calculations. 
THE current number of the /owrnal of the Anthropological 
Institute fully maintains the great reputation which that publica- 
tion has earned. There are three papers on customs and 
beliefs of various African tribes, one on a remarkable musical 
