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parts to them that peculiar color. The greenish portions he inferred to be
Among the features apparent on this planet, what attracted most attention are certain white spots seen around the polar regions. These were among the very first permanent marks discovered on the planet, and are represented even in the first rude drawing given of its telescopic appearances in the proceedings. of the Royal Society. In the observations of Herschel-both father and sonthey have, however, been more rigorously examined and described; and still more so in the investigations of Beer and Mädler.
It has been ascertained from the changes they undergo that they must be produced by deposites of snow in the polar regions. Herschel observed that when the pole had been turned from the sun during the winter, and first reappeared in the spring of the planet, the whiteness was most extensive and vivid; and that when the same pole was exposed to the influence of the sun during the summer, which is double the length of the summer upon the earth, this whiteness gradually diminished, and always disappeared. Such indications cannot be mistaken, and admit of no other explanations save what I have now adverted to.
The elaborate observations of Beer and Mädler have supplied various telescopic views of this planet. In their work upon this subject they have published forty views of hemispheres made by planes passing nearly through the poles, which is the only view presented to the observer by the planet. Having, by combining together many observations, made as it were a survey of the entire surface of the globe of Mars, they have given two views, one of its northern and the other of its southern hemisphere.
We have obtained copies of these views, and have affixed them here. Two of the views of this planet, bounded by a circle passing nearly through its poles, are annexed. The views of the hemispheres are given on page 12.
Analogy naturally suggests the probability that the planet Mars might have a moon. These attendants appear to be supplied to the planets in augmented numbers as they recede from the sun; and if this analogy were complete, it would justify the inference that Mars must at least have one, being more remote from the sun than the earth, which is supplied with a satellite. moon has ever been discovered in connexion with Mars. It has, however, been contended that we are not therefore to conclude that the planet is destitute of such an appendage; for as all secondary planets are much less than their primaries, and as Mars is by far the smallest of the superior planets, its satellite, if such existed, must be extremely small. The second satellite of Jupiter is only the forty-third part of the diameter of the planet; and a satellite which would only be the forty-third part of the diameter of Mars, would be under one hundred miles in diameter. Such an object could scarcely be dis
covered, even by powerful telescopes, especially if it did not recede far from the disk of the planet.
The distance of Mars from the sun being greater than that of the earth in the proportion of three to two, it follows that the apparent magnitude of the sun to the inhabitants of Mars will be less than to the inhabitants of the earth in the same proportion. In the annexed diagram, if E represents the appearance of the sun to the earth, M will represent its appearance at Mars.
The light which it affords will be in the same proportion as its apparent magnitude; and as the superficial magnitude of the disk will be about half that which it presents to the earth, it follows that the intensity of the sun's light at Mars will be less in the same proportion. But, for the reasons which have been elsewhere stated, no safe inference can be made respecting the effect of the sun on the temperature of the planets.
The close analogy in which this planet stands to the earth will be apparent
to those who have considered the facts and phenomena now described. It is a globe whose diurnal motion is such as to give it days of the same length; its seasons succeeding each other in the same manner, and are limited by the same extremes of temperature. Its latitudes are diversified by the same torrid, temperate, and frigid zones, and the same varieties of climate. Its surface is characterized by a like distribution of land and water; and, like the earth, it has its continents, islands, and seas. It is invested with an atmosphere, supplying doubtless all the interesting objects and advantages which result from
Merits of Weather Almanacs.-Excitability of the London Public.--Fright produced by Biela's Comet.-London Water Panic.-London Air Panic.-London Bread Panic.-Rage for Weather Almanacs-Patrick Murphy's Pretensions.-Examination of the Predictions of the Weather Almanac. Their Absurdity.-Comparison of the Predictions with the Event-Morrison's Weather Almanac--Charlatanism of these Publications.-Great Frost of 1838 in London.--Other Visita tions of Cold.