86 
POPULAR SCIENCE REVIEW. 
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candescent, and the light from it is in large part unpolarised ; on the other 
hand, the light from the outer part of the corona is mixed up with light from 
our own atmosphere, drowning the polarisation of the outer corona. 
Meteoric Theory of the Corona. — Mr. Penrose infers from the observed 
aspect of the coronal streamers that they are due to meteoric systems. “ I 
am far from arguing,” he says, 11 that this theory answers for the whole of 
the corona, and I much doubt whether it will explain the almost equal and 
radial lines which proceeded from the neighbourhood of the sun’s north pole, 
and which appeared to me the most beautiful part of the whole. There was 
also something analogous near the sun’s south pole, but not so clearly radial. 
The pointed ends of the 1 wind vane’ (a name suggested by the shape of two 
opposite sets of streamers) seem to suggest the explanation of an elliptic orbit 
of considerable major axis and great eccentricity. The wedge-like point 
proceeding from the north pole of the sun would agree with a similar figure, 
whilst some of the others can be explained by orbits of meteors of less ex- 
tent. It is obviously not requisite that the sun’s centre should be the focus 
of the apparent orbit, as it would be modified from the real figure by per- 
spective.” 
Foreign Obsei'vations of Meteor Showers . — Prom observations recorded by 
Heis, Weiss, Schiaparelli, Zezioli, and Konkoly, Mr. Denning has drawn up a 
useful list of 79 meteor showers in the Notices of the Astronomical Society 
for November. We observe that he still fails to recognise the validity of 
the objections raised by Captain Tupman and others, against his idea that 
meteors belonging to the same system can appear to radiate from the same 
point in the sidereal heavens for several successive weeks. He seems to suppose 
that planetary perturbations acting on attenuated meteor streams might 
diffuse them, so that a considerable time would be required for the earth’s 
passage through them, while the radiant points remained sensibly unaltered. 
He says it “ has yet to be ascertained ” whether this is possible. But no- 
thing can be more certain than that this is utterly impossible. He ap- 
pears also to suppose that the results of observation are questioned by Captain 
Tupman and the other objectors. “ Observers will state the legitimate re- 
sult of their labours,” he says, “ apart from theoretical considerations, however 
incompatible they may at first appear.” It was to his interpretation of his re- 
sults that exception was taken, not to the results themselves. If observers 
have obtained clear evidence showing that at different times between the 
middle of October (to take one case) and the middle of December, meteors 
radiate from the same point of the stellar heavens, their statement must be 
accepted. But when they proceed to assert that, therefore, the meteors so 
seen belong to one system, the mathematician perceives that the inference is 
entirely erroneous. It is absolutely certain, if the results of observation are 
admitted, that the meteors belong to different systems. The reasoning runs 
simply thus: — We know that the members of a meteor system are bodies 
travelling around the sun in orbits passing near the earth’s ; and that their 
“ radiant ” at any given date is a point depending on the combination of their 
motion with the motion of our earth, the direction as well as the velocity of 
each motion being involved. If, then, it were possible for a meteor system 
to be so widespread that the earth required eight or nine weeks to pass 
through it, and even if the directions of the meteors at all parts of her arc of 
