566 KANSAS CITY REVIEW OF SCIENCE. 
meteoric dust rather than of differences of density in the atmosphere leading to 
extraordinary refraction. 
In the first place the phenomenon has not only been visible over an immense 
extent of territory, but it has lasted several days, and has been seen in the east 
before sunrise, as well as in the west after sunset, so that any abnormal refrac- 
tion in the atmosphere would have to be of almost incredible persistence in order 
to account for the observed appearances. Besides, during this time there have 
been considerable atmospheric changes, especially in respect to temperature. 
These remarkable sunset displays have also been accompanied by a notably hazy 
appearance of the sky. 
It is well known that the earth is daily and nightly pelted with millions of 
meteors, the vast majority of which are almost instantly consumed by the intense 
heat developed as they dash into our atmosphere. The products of the combus- 
tion of these meteors filter slowly down through the air, and have been found in 
the shape of metallic dust on the snow fields in the Arctic regions, on mountain 
peaks in Europe and in other similar localities, being recognizable by their pe- 
culiar chemical composition. It is also known that the solar system abounds 
with swarms of meteors revolving around the Sun, and that the earth crosses the 
path of a number of these, occasionally encountering the swarms themselves. 
The vast majority of these meteors are very small, those that are seen weighing 
on an average probably only a few grains ; and since the telescope reveals mill- 
ions which escape the naked eye, it is reasonable to conclude that millions more 
are too small to be seen with telescopes — mere meteoric dust. Professor Brook's 
suggestion that the earth has encountered a cloud of meteoric dust is not, there- 
fore, without foundation in probability. If the recent blazing sunsets have really 
resulted from such a cause, they are likely to continue, in a modified form, for 
some time, gradually disappearing as the dust sinks lower in the atmosphere. 
But although so many reasons can be advanced which give probability to the 
theory that meteoric dust is concerned in the production of these strange sunset 
effects, yet it cannot be considered as proved, and some better explanation may 
be offered. Whatever the true explanation may turn out to be, however, every- 
body seems to agree in the opinion that the red glare in the west during the last 
three or four evenings has been one of the most singular spectacles beheld in the 
sky for many years. 
At a meeting of the American Astronomical Society, in New York, a few 
days ago, three theories were advanced. One would have it that the brilliant 
redness in the evening sky was caused by reflection from banks of clouds below 
the horizon. Another held that the curious appearance was produced by the 
passage of the sun's rays through strata of the atmosphere heavily laden with 
moisture, which absorbed the violet elements, but let the red go on. According 
to the third notion, which is that most generally accepted, the earth has just pen- 
etrated vast clouds of meteoric dust, which occasioned the phenomenon. 
