8 NAL ORE 
[MARCH 7, 1912 
Sounds of two distinct types accompanied the agita- 
tion. The first consisted of whistling sounds, like 
that of numerous long-lashed whips swishing rapidly 
through the air, or perhaps that of the whistle of 
bullets. These sounds seemed to be associated with 
the general field of fainter blue. 
The other sounds consisted of the characteristic 
crackle of electricity, and these became so numerous 
as they approached the climax that they resembled a 
magnified rustle. These cracklings seemed to be 
associated with forked discharges, and were probably 
due to the more distinct fiashes coming into contact 
with the bushes which surround the plateau. 
The phenomenon lasted about fifteen to twenty 
seconds, and disappeared as spontaneously as it had 
arisen. J. McV. M. 
Tue phenomenon described above appears to have 
been the luminous discharge known as St. Elmo’s 
Fire. This talkes place usually from pointed objects, 
and possibly the tree in your correspondent’s sketch 
(not reproduced) played a part in the production of 
the phenomenon. ‘The colour associated with St. 
Elmo’s Fire depends upon the character of the dis- 
charge. It is blue when the earth is kathode and red 
when the earth is anode. 
The discharge is not infrequent in mountainous 
countries. E. Goxp. 
Hampstead Garden Suburb, N.W. 
Earthworms and Sheep-rot. 
EVERYONE who is interested in agriculture is aware 
that liver-fluke or sheep-rot is popularly associated 
with one or another of our common plants. Halliwell 
gives ‘“sheep-killing ’? as a name for ‘the herb 
pennywort.’’ ‘In Britten and Holland (‘‘ English Plant 
Names’’) we find sheep-rot, sheep-bane, and other 
similar terms, and we are told that such plants as 
Pinguicula vulgaris, L., and Hydrocotyle vulgaris, 
L., are known by these popular names because of a 
supposition that these plants cause the liver-rot in 
sheep, which disease is often prevalent on wet land 
where the plants grow. The authors further inform 
us that “It is now ascertained that the liver-fluke, 
which always accompanies rot in sheep, exists.in one 
of its stages as a parasite in the bodies of small water 
snails, which, in wet weather, creep upon the leaves 
of marsh plants, and are eaten by the sheep with 
the herbage. It is therefore. with some reason that 
such names as ‘ Flowlkwort,’ ‘ Sheep-Kkilling Penny- 
grass,’ and ‘ Sheep-rot’ have been given to these 
marsh plants.” 
Withering (‘British Plants’’) has a similar note. 
Speaking of Pinguicula, he says, ‘‘The plant is 
generally supposed injurious to sheep, occasioning 
a disease which the farmers call ‘ rot.’ But it may be 
questionable whether the rot in sheep is so much 
owing to the vegetables in marshy grounds, as to a 
flat insect called a fluke (Fasciola hepatica), which is 
found in these wet situations adhering to the stones 
and plants, and likewise in the livers and _ biliary 
ducts of sheep that are affected with the rot. From 
experiments conducted with accuracy, it appears that 
neither sheep, cows, horses, goats, nor swine feed 
upon this plant.” 
During a recent visit to Cumberland, however, the 
matter was presented to me in a new light. I was 
conversing with a farmer on the economy of the 
earthworm, when my friend protested that they were 
responsible for rot in sheep. His explanation was as 
follows. The worms make casts in spring, known 
in the north as worm-sprouts, just as in the eastern 
NO. 2210, VOL. 89] 
counties they are called worm-puts. On these fine 
young plants grow rapidly, proving very attractive to 
sheep. When the sheep feed on this tender grass 
they are liable to suffer from fluke, and it is therefore 
maintained that the fluke, or rot, is in some way 
due to the earthworm. 
It would be interesting to know more about this 
popular fancy, and to learn whether anything is being 
done to help farmers to a more correct knowledge 
of the facts. HiLperic FRIEND. 
Swadlincote, Burton-on-Trent, February 17. 
Meteor-showers. 
I am sure that a great many of your readers who 
are interested in the subject: of meteors have noticed 
the letters of Mr. John R.-Henry which have appeared 
from time to time in your columns, but I do not 
recollect having seen any letter from an observer stat- 
ing either that Mr. Henry’s prediction had been ful- 
filled or that it had failed. If a shower of the thirty- 
third magnitude is sufficiently marked to enable three 
secondary maxima to be fixed with accuracy, one of 
the third magnitude, such as we are promised at the 
end of this month (February) ought to be very per- 
ceptible indeed.. But perhaps the word ‘‘ magnitude”’ 
does not refer to the number of the meteors but ta 
their average mass. If so, how is this mass to be 
ascertained? Mr. Henry gives us no information as 
to the part of the sky in which these meteors should 
on each occasion be looked for. F.R.A.S. 
Dublin. 
“ELR.A.S.”’ is right in surmising that the mag- 
nitude of a shower does not depend upon the number 
of meteors that may be actually observed, but rather 
upon the general mass or quantity of matter imported 
into the atmosphere at the time. This may appear 
to be a distinction without a difference, but as the 
number of shooting stars counted by an observer will 
be influenced by the altitude of the radiant, the clear- 
ness of the sky, &c., it is evident that the intensity 
of the phenomenon cannot be fully measured by such 
results. It is assumed that the radiant is the same 
as that usually associated with the time of the year 
at which the shower occurs. 
To determine the absolute mass of a meteor-shower 
is a somewhat intricate problem, but it is possible 
to obtain an approximate solution of it by assumir™ 
that the portion of the meteor-swarm which enters the 
atmosphere is moving nearly parallel to the earth’s 
surface, and in being brought to rest puts the sur- 
rounding air in motion. There must thus result an 
atmospheric depression, and given the mean depth 
and extent of the latter, the mass of the shower may 
be calculated from purely dynamical principles. 
The order of magnitude does not express, as may 
be supposed, the absolute but rather the relative 
intensity of a shower, with reference to some other 
shower which may be regarded as the standard- 
shower. Thus of the two showers referred to by 
“TOR.A.S.,”” one of the thirty-third, and the other 
at the end of February of the third order of mag- 
nitude, the former is of the weakest and the latter of 
the highest intensity in the whole month. The 
greater meteoric event, apart from its high intensity, 
happens to belong to an interesting type or group of 
meteor-showers, one of which of the tenth order of 
magnitude occurred in 1908 on September 28, and 
another of the eighteenth order in torr, on April 
8-9, both occasions being marked by a magnetic and 
the latter also by a moderate seismic disturbance. 
Joun R Henry. 
