Page:Popular Science Monthly Volume 46.djvu/860

840 always in good health, being "temperate in all things," and, though often furnishing wine for his guests, declining the use of it himself, as he said he wished to keep his head always perfectly clear. To tobacco in all its forms he had a great aversion. One of his theories was that human life was much too short, either because of too much luxury and self-indulgence on the one hand, or lack of proper sustenance on the other. By striking the happy medium, he believed life might be indefinitely prolonged. His last illness was of about three weeks' duration, and caused by a carbuncle on the upper lip. After a time the brain became affected and unconsciousness ensued, which continued uninterruptedly until he passed away, having seen but fifty-five and a half years. This early ending of his life seems like the irony of Fate! The many letters received by the family after his death, from those with whom he had been associated in his scientific career, filled with such heartfelt expressions of sorrow and regret for the personal loss and the loss to science, attest to the estimation in which he was held by them all.

The original of the likeness accompanying this sketch was a daguerreotype—the only portrait of any kind ever made of Prof. Vanuxem. This was taken in a group in 18-40, in the early days of the art, when the arrangement of dress and pose was not understood so well as afterward. Hence the eyes, said to have been his best feature, are unfortunately cast down, as he was told to look at the child seated on his knee. The portrait is like him, but has not the pleasing aspect his countenance always wore.

appears from a discussion by Prof. Holden, of the Lick Observatory, of the smallest object on the moon that can be registered on the photographic plate by the three-foot refractor, that a crater on that star less than one tenth of a mile in diameter will form an image that is about the same size as the grains of silver in the photographic film, and can not in general be distinguished. Craters not more than three tenths and fifteen hundredths of an English mile in diameter, however, have been detected already. Prof. Holden concludes that for further advances in lunar photography it will be necessary to employ plates of greater sensitiveness so as to shorten exposure, and also plates in which the grain is finer.

The "southerly bursters" of Australia are storms that occur very suddenly, and mostly between November and February. A fresh northeasterly wind may change in ten minutes to a gale from the south, doing much damage to vessels that may be unprepared. The storms are always accompanied or preceded with great electrical excitement, and cause a considerable drop in the temperature. The wind velocity used to reach from sixty to eighty miles an hour, and on one occasion attained the rate of more than a hundred and fifty miles an hour, in a gust. Latterly, however, the wind seldom exceeds fifty miles, and generally ranges between thirty and forty miles an hour. The average annual number of storms is thirty-two.