Feb. 1, 1883] 
NATURE 315 
The first elliptical orbit calculated by Mr. J. C. Chandler, using 
observations from September 18 to October 20, gave a period 
of about 4000 years. 
Afterwards Mr. Kreutz, using observations from September 
8 to November 14, gave a period of 843 years, and lately Mr. 
Morrison, keeping observations from September 19 to De- 
cember 11, has an elliptical orbit with only 642°5 years. 
This fact induces me to believe that an accurate study of the 
perturbations of the motion of this comet may be as important 
as it was for Biela’s comet. 
It is my purpose to go, as far as I can, through a com- 
plete discussion of all the observations, and I shall be very 
glad if those of your readers, who are possessors of good un- 
published remarks both about the appearance and about the 
positions of the comet, would kindly let me know of them. 
E, RIsToRI 
13, Pembridge Crescent, Bayswater, W., January 30 
The Aurora of November 17, 1882 
I sHOULD like to ask H. J. H. Groneman whether he tried 
to find out if a curved path for the auroral beam would agree 
better with the observations than a straizht one; because, if it 
was purely an auroral phenomenon, we should naturally expect 
its path to be a curve, maintaining a uniform height above the 
surface of the earth, and to be approximately a small circle 
having its centre at the magnetic pole, this being the ordinary 
position of the aurora] arches. Of course the motion of the 
parts of the arch is often not exactly in this direction, because 
the arch has frequenily a tran:verse motion in addition to the 
movements that take place longitudinally ; and if there was any 
such transverse motion in the case of this beam, that would 
prevent its moving strictly along a parallel of magnetic latitude, 
though it is hardly likely it would deviate far from it. It would 
be well to ascertain whether such a motion would not agree 
better with the observations of the beam than Dr. Grone- 
man’s hypothesis that it was in a straight line; for the establish- 
ment of a curved motion would do away with the idea that the 
phenomenon was caused by a meteor. 
In the other cases cited by Dr. Groneman of supposed 
meteoric masses passing through our atmosphere and producing 
auroral effects, the paths, so far as given, seem all to have been 
approximately along the parallels of magnetic latitude, which 
circumstance militates against their having had anything to do 
with meteors, because these traverse the atmosphere in all direc- 
tions, and would be just as likely to go in a northerly or 
southerly direction as ia an easterly or westerly one. Possibly, 
however, Dr. Groneman’s theory may be that meteors only 
produce an auroral effect when they happen to go in such direc- 
tions as may be calculated to produce it. 
Sunderland, January 29 TuHos, WM. BACKHOUSE 
As Dr. Groneman in his most interesting paper on the pheno- 
menon of November 17 asks for my authority for the Swedish 
observation, I may say that J merely saw it in the ‘‘ Notes” in 
NATURE (vol. xxvii. p. 113). There seems a misprint in that 
statement, however, as ‘‘ Eskibstuna, fifty-four miles south of 
Stockholm ” would be in the sea, whereas Eski/stuna is fifty-four 
miles west of Stockholm. i 
As the spectroscope observation is said to put the auroral 
nature of the ‘‘spindle” beyond doubt, I would observe that 
until we know that gas excited by the passage of particles 
through it at fifteen miles a second does not give the same 
spectrum as when incandescent by an electric discharge, the 
observation of certain lines cannot prove anything of the exciting 
cause, Further, a good deal of the light might be reflected sun- 
light, as that would be scattered over the whole spectrum, and 
would thus be masked by the faint diffused spectrum of the 
moonlight at the time. W. M. F. PETRIE 
Bromley, Kent 
REFERRING to Dr. G:oneman’s communication, possibly it 
may be of service to say that at 9 p.m., October 14, 1870, 
besides some ruddy aurore, chiefly in the west and north, I saw 
a band having a very close resemblance to that figured in the illus- 
tration, p. 297. It, however, stretched all the way across the sky 
from west to east, and continued for some time without much 
apparent alteration in figure or locality. An appointment called 
me away before it had vanished. HENRY MUIRHEAD 
Cambuslang, January 26 
The Sea Serpent 
I HAVE seen four or five times something like what your cor- 
respondent describes and figures, at Llandudno, crossing from 
the Little Ormes head across the bay, and have no doubt what- 
ever that the phenomenon was simply a shoal of porpoises. I 
never, however, saw the head your correspondent gives, but in 
other respects what I have seen was exactly the same ; the 
motions of porpoises might easily be taken for those of a serpent ; 
once I saw them from the top of the Little Orme, they came very 
near the base of the rock, and kept the line nearly half across 
the bay. JOSEPH SIDEBOTHAM 
Erlesdene, Bowdon, January 26 
Influence of ‘‘ Environment” upon Plants 
REFERRING to Prof, Thiselton Dyer’s letter on the above 
subject in NATURE (vol. xxvii. p. 82), it may interest your 
readers to know that I have had several trees of Acacta dealbata 
30 feet high, in the open air, in flower for ten days past, but not 
so fully as they will be in a fortnight’s time. I have had 
Desfontainea spinosa in flower during the past eight months ; this 
shrub is 64 feet high, and al-o in the open air. 
Rosehill, Falmouth, January 29 
Howarp Fox 
THE PEAK OF TENERIFFE ACTIVE AGAIN 
PRIVATE letter which I have just been privileged 
to see, from: a native lady in Santa Cruz to her 
sister in this country, tells how the inhabitants of that 
present capital of Teneriffe had remarked for several 
months past, that there was no snow on the upper part of 
the Peak; though all the “ Cumbree,’’ or moderately high 
land over the rest of the island, was whitened with it in 
the usual manner for the season. But within the past 
few days, “ fire, like three great bonfires’’ had been seen 
on the summit of the Peak, and a lava stream had begun 
to flow down from it. 
Now this is interesting both chronologically, and choro- 
graphically. Chronologically, I had remarked at p. 150 
of my little book ‘‘ Teneriffe an Astronomer’s Experi- 
ment,” (published in 1858), that the lava eruptions there 
only break out about once in a century ; the last eruption 
having occurred in 1798, and the previous one in 1703; 
and now we have one in 1883, but in what part of the 
mountainous island called Teneriffe has this last eruption 
appeared ? 
So far as I can gather from the said private letter, it 
has issued, if not from the very mouth of the craterlet 
which forms the tip-top of the Peak, yet from its sides or 
foot where it stands on a filled up crater of much larger 
size, otherwise to be looked on as the Peak’s proper and 
effective summit; and it is from that crater’s lips that 
have proceeded all the later, and yet prehistoric, streams 
of black lava, which score and frill the Peak on every 
side ; and contrast so strikingly with the far more ancient 
red, and the still more ancient, more abundant, and once 
hotter yellow streams from the older and larger craters 
lower down, before ever yet, the Peak, or final cinder 
heap, was formed. 
But though in the Nature-primeval history of the 
Mountain, the black, unoxydised lava streams of the 
Peak, were its latest exudations, still nothing more of that 
kind was locally expected to occur there within the human 
period. This was partly because no addition to them had 
been made since the Spanish Conquest ; and partly be- 
cause the lava outflow of 1798 avoided the Peak, and 
broke out on the Western side of the general mountain 
mass, while the eruptions of 1703, which threatened the 
town of Guimar to the south, and destroyed Garachico to 
the north, filling up its once beautiful bay—broke forth 
nearer the sea-level than the peak’s top. Whence the 
idea arose, that the central vent of the peak must have 
clogged up with time, and that nothing more than its 
merry little jets of steam and sulphurous acid were to be 
looked for in that quarter ; yet now we are told of red 
hot lava pouring forth. 
