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NATURE 
[May 5, 1870 
the plain fora considerable distance. When winged they 
make for the nearest burrow, and when once within it, it 
is impossible to dislodge them.” It is commonly said that 
rattlesnakes are likewise abundant in these “ Prairie-dog 
villages,” and that the beast, bird, and reptile, may not 
unfrequently be seen here in harmonious juxtaposition. 
In the pampas of South America, this little owl associates 
with another Burrowing rodent, which lives in communi- 
ties in a similar manner to the Prairie-dog. This is the 
Vizcacha (Lagostomus trichodactylus). During the open 
day, Mr. Darwin tells us, but more especially in the 
evening, these owls may be seen in the pampas of the 
Argentine Republic in every direction, standing by pairs 
on the hillock next to their hole. If disturbed, they either 
retreat under-ground, or move with an undulatory flight 
to a short distance, and then turning round, steadily gaze 
at their pursuer. 
The Burrowing Owl is, however, perfectly capable of 
making its own burrow, as Mr. Darwin tells us it always 
does where the Vizcacha is not found, and as it has done 
in the Zoological Society’s Gardens. The first individual 
of this species which was received in 1868 from the 
same donor, was no sooner placed in a cage with a sandy 
floor than, “true to its habits, it excavated a hole in the 
soil at the bottom, into which it always retreated when 
threatened.” The same habit may be witnessed on 
alarming the specimens of this bird now in the Society’s 
gardens, although the burrow in the present instance has 
been, at all events partially, made artificially for their use. 
(4.) An example of a rather rare Antelope from Western 
Africa—the Woodloving Antelope (Cephalophus sylvicul- 
tyix)—received in exchange March 24th. This is a 
representative of a group of Antelopes of small size 
which are found only in tropical or subtropical Africa, 
and are peculiar for having a little tuft of hair between 
their horns, as their generic name imports. Some eighteen 
or twenty species of this genus are known to science, and 
several of them are usually represented in the Zoological 
Society’s collection. But the present animal, which is 
well marked by its white dorsal streak, has not been pre- 
viously received alive by the Society. P. L. SCLATER 
NOVEL TELEGRAPHY — ELECTRIFICATION 
OF AN ISLAND 
CURIOUS discovery has been made by Mr. Gott, the 
superintendent of the French company’s telegraph 
station at the little island of St. Pierre Miquelon. There 
are two telegraph stations on the island. One, worked in 
connection with the Anglo-American company’s lines by 
an American company, receives messages from Newfound- 
land and sends them on to Sydney, using for the latter 
purpose a powerful battery and the ordinary Morse signals. 
The second station is worked by the French Trans- 
atlantic Company, and is furnished with exceedingly deli- 
cate receiving instruments, the invention of Sir William 
Thomson, and used to receive messages from Brest and 
Duxbury. These very sensitive instruments were found to 
be seriously affected by earth-currents ; ze., currents de- 
pending on some rapid changes in the electrical condition 
of the island ; these numerous changes caused currents to 
flow in and out of the French company’s cables, interfering 
very much with the currents indicating true signals. This 
phenomenon is not an uncommon one, and the inconve- 
nience was removed by laying an insulated wire about three 
miles long back from the station to the sea, in which a large 
metal plate was immersed ; this plate is used in practice 
as the earth of the St. Pierre station, the changes in 
the electrical condition or potential of the sea being small 
and slow, in comparison with those of the dry rocky soil of 
St. Pierre. After this had been done, it was found that part 
of the so-called earth-currents had been due to the signals 
sent bythe American company into their own lines, for when 
the delicate receiving instrument was placed between the 
earth at the French station and the earth at the sea, so 
as to bein circuit with the three miles of insu- 
lated wire, the messages sent by the rival com- 
pany were clearly indicated, so clearly indeed, 
that they have been automatically recorded by 
i Sir William Thomson’s syphon recorder. An- 
nexed is a facsimile of a small part of the 
message concerning the loss of the steamship 
Oneida, stolen in this manner. 
It must be clearly understood that the Ameri- 
can lines come nowhere into contact, or even 
into the neighbourhood of the French line. The 
two stations are several hundred yards apart, 
and yet messages sent at one station are dis- 
tinctly read at the other station ; the only con- 
nection between the two being through the earth ; 
and it is quite clear that they would be so re- 
: ~ ceived and read at fifty stations in the neighbour- 
? ™ hood all at once. The explanation is obvious 
‘S enough: the potential of the ground in the neigh- 
ae bourhood of the stations is alternately raised and 
lowered by the powerful battery used to send 
the American signals. The potential of the sea 
at the other end of the short insulated line re- 
mains almost if not wholly unaffected by these, 
and thus the island acts like a sort of great 
Leyden jar, continually charged by the American 
battery, and discharged in part through the 
short insulated French line. Each time the 
American operator depresses his sending key, 
he not only sends a current through his lines, 
but electrifies the whole island, and this elec- 
trification is detected and recorded by the rival 
company’s instruments. 
No similar experiment could be made in the 
neighbourhood of a station from which many 
simultaneous signals were being sent; but it is 
perfectly clear that unless special precautions are 
taken at isolated stations, an inquisitive neigh- 
bour owning a short insulated wire might steal 
all messages without making any connection 
line. Stealing messages by attaching an in- 
strument to the line was a familiar incident in 
the American War ; but now messages may be 
stolen with perfect secrecy by persons who no- 
where come within a quarter of a mile of the 
line. Luckily, the remedy is simple enough. 
~ 
= 
i 
All owners of important isolated stations should use 
earth-plates at sea, and at sea only. This plan was 
devised by Mr. C. Varley many years ago to eliminate what 
we may term natural earth-currents, and now it should be 
used to avoid the production of artificial earth-currents 
which may be improperly made use of. 
FLEEMING JENKIN 
NOTES 
WE regret to hear that Baron Liebig is very ill. 
WE are informed that Messrs. Lyon Playfair, C.B., M.P., 
B. Samuelson, M.P., and Dr. W. A. Miller, will probably 
be among the members of the Royal Commission to inquire into 
the Present State of Science in this country. 
PRINCIPAL DAwsoN, of Montreal, who is now ona visit to this 
country, will deliver the Bakerian Lecture to-night before the 
Royal Society. The subject is the Pre-carboniferous Flora of 
North Eastern America, The opportunity of listening to so emi- 
nent a geologist on a subject which he has made especially his 
own, will doubtless draw together a large assembly of our men of 
science anxious to do honour to their distinguished con/rére. 
THE following gentlemen have been appointed by the Uni- 
versity of London examiners and assistant examiners for 1870- 
between his instrument and the cable or land — 
