556 
electric field is violently disturbed. Various types of potential 
are illustrated by reproductions of photographic curves of a 
self-recording electrometer, 
Ir is often necessary in experimental work to maintain 
a condenser continuously charged at a constant high poten- 
tial for a considerable length of time, and various methods, 
none of them altogether satisfactory, have been proposed. 
An ‘‘electrostatic relay”’ suitable for this purpose is described 
by M. V. Crémieu in the Journal de Physique for September. 
The form hitherto found most satisfactory depends essentially 
on the action of an electrostatic balance, which automatically 
makes or breaks contact in an electric circuit when the potential 
passes a certain value, thereby connecting or disconnecting the 
condenser to be charged and an electrostatic machine. The 
objection to this arrangement arises from the fact that a certain 
force is necessary either to make or break the contact, and 
hence the potential of the condenser may fluctuate as much as 
22 per cent. The arrangement which M. Crémieu now pro- 
poses obviates this difficulty. In one of the contacts there is 
no adhesion of the terminals and no sparking, because when 
the contact is made only a very small quantity of electricity 
flows through it, and when it is broken the terminals are both 
at the same potential. In the only contact in which adhesion 
may occur, the terminals are separated by a force which can by 
adjustment of the apparatus be made as large as desired. It 
results that the present arrangement is capable of regulating 
the potential of a condenser of 1 kilometre capacity, charged up 
to 5000 volts, to within 4 per cent. 
Mr. J. L. WorTMAN contributes part i. of ‘Studies of Eocene 
Mammalia in the Marsh Collection, Peabody Museum” (Amer. 
Journ, Science, ser. 4, vols. xi.—xiv., 1901-1902). In this work 
the Carnivora are dealt with, the ancestral relations and pro- 
gressive modifications of the several families are considered, 
some new genera and species are described, others are freshly 
defined, and some, like Triacodon, Ziphacodon and Harpalodon, 
are not regarded as valid genera. The author also discusses the 
general organisation of the Carnivora and the relationship of its 
more primitive members to the metatherian marsupials. 
IN an exhaustive memoir relative to the Mexican meteorites 
which was published in the AZ2eralogical Magazine in 1890 
(vol. ix. pp. 91-178), Mr. Fletcher called attention to the fact 
that a large mass of meteoric iron, found in 1867 in an ancient 
grave at Casas Grandes de Malintzin, Chihuahua, Mexico, and 
thus of much archeological interest, had not been heard of since 
1873, in which year it was said to be about to be transported 
from Casas Grandes to the United States consulate at El Paso. 
Mr. Fletcher suggested that the missing mass was possibly 
identical with one which had been shown in the Mexican 
mineral exhibit at the United States International Exhibition 
of 1876 and had been afterwards transferred to the Smithsonian 
Institution. On investigation, the Washington authorities were 
convinced that the suggestion was well founded. Mr. Wirt 
Tassin has now published (Proceedings of the United States 
National Museum, 1902, vol. xxv. p. 69) a description of the 
mineralogical and chemical characters of the mass. Very sharply 
defined Widmanstitten figures are developed by the etching of 
a polished face. The percentage of nickel (and cobalt). varies in 
different parts from 4°5 to 5°3. The chemical composition of 
one of the alloys (tzenite) corresponds to the formula Fe,Ni. As 
is usual in meteoric irons, both troilite (ferrous sulphide) and 
schreibersite (phosphide of iron and nickel) are present ; both 
minerals were isolated and analysed. Cliftonite, the cubic form 
of graphitic carbon, was carefully sought for, but only massive 
grap hitic carbon was found. 
NO. 1718, VOL. 66] 
NATURE 
| OCTOBER 2, 1902 
IN the course of an interesting paper on the crustacean fauna 
of the Mammoth Cave, Kentucky, and its neighbourhood, 
forming No. 1285 of the Proceedings of the U.S. Museum, 
Mr. W. P. Lay describes a new form of blind shrimp discovered 
by himself in one of the streams passing through the cave. This 
shrimp, which belongs to a family previously unknown from the 
North American Continent, is referred to a new genus, although 
it appears to come very close to Xiphocaris, of which one 
representative is found in the West Indies, a second in New 
Zealand and a third in the Indo-Malay region. The author is 
of opinion that the group is a very ancient one and that the 
cave-forms have survived in districts whence their relatives have 
migrated south. 
Tue Report of the Director of the Botanical Survey for the 
year 1901-1902 has been received, and includes the independent 
reports of the directors of the three botanical departments. 
The chief items of interest are the failure of attempts to 
introduce the plant Paspalum dilatatum, which has a consider- 
able reputation in America and Australia as a drought-resisting 
fodder grass, hybridisation experiments with wheat, and various 
sugar-cane pests and diseases. 
WE have received a subject list of works on domestic 
economy, foods and beverages, including the culture of cacao, 
coffee, barley, hops, sugar, tea and the grape, in the library of 
the Patent Office. The list comprises 1270 works. 
THE September issue of the Agrzcultural Journal of the Cape 
of Good Hope contains a powerful plea for the use of the metric 
system in South Africa from the pen of Mr. D. E. Hutchins, 
conservator of forests, western districts of Cape Colony. The 
number also contains the communications on the ‘‘ Misuse of 
Coal” by Prof. John Perry, F.R.S., and Mr. Hutchins which 
appeared in our columns on March 20 and July 10 respectively. 
THE same number of the journal has a note upon some 
French experiments which have been made respecting the use 
of salt in the dietary of sheep. Three lots of sheep were fed 
identically, excepting that one lot had no salt, another lot had 
half an ounce every day and the remainder three-quarters of an 
ounce daily. Those receiving half an ounce gained 4°5 pounds 
each more than those which had no salt and 1°25 pounds more 
than those which had more thar half an ounce. The salted 
sheep had 1°75 pounds more wool and a better fleece than 
those which had no salt. 
THE current issue of Hxgineering contains a description of 
the proposed scheme for the transmission of letters, newspapers 
and parcels by an aérial electric railway which is at present 
under the consideration of the Italian Minister of Posts and 
Telegraphs, to which we briefly referred in our columns of 
September 18. 
THE 7%mes of Thursday last contains an interesting account, 
by Mr. J. Y. Buchanan, F.R.S., of the recently completed 
fourth annual scientific cruise of the Prince of Monaco’s steam 
yacht Princesse Alice. 
A NEW edition, the sixth, of Lord Avebury’s ‘‘ The Origin of 
Civilisation and the Primitive Condition of Man” has just been 
issued by Messrs. Longmansand Co. The author, in his preface, 
states that he sees no reason to change in any essential 
respects the opinions originally expressed by him in the first 
edition of the book thirty years ago. The present issue of 
the work contains, however, numerous additions here and 
there. 
THE Report of the proceedings and abstracts of the papers 
read at the International Engineering Congress held in Glasgow 
in 1901 has been issued in volume form by Mr. W. Asher, of 
Glasgow. 
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