Page:Popular Science Monthly Volume 22.djvu/308

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THE POPULAR SCIENCE MONTHLY.

into an indefinite nebulosity, and the dark stripe had become much fainter.

Continued bad weather prevented observation until the 10th, and on this date the nine-and-a-half-inch telescope of the School of Science Observatory was used. A great change had taken place. The nucleus had become an irregular, spindle-shaped streak some 40" long, made up of six or eight star-like knots of luminosity connected and veiled by shining haze. One of these knots, about a third of the way from the sunward extremity, was considerably larger and brighter than any of the others, and should, perhaps, be considered as the true nucleus. The next one beyond it (reckoning from the direction of the sun) was second in size, and separated by an interval of 2" or 3", the space being filled, however, with nebulosity. The dark stripe was still visible, but directed, not along the prolongation of the nuclear streak, but inclined at an angle of 8° or 10°, while a bright jet from the nucleus, two or three minutes in length, touched one side of the dark stripe, and kept nearly in the axis of the tail. Fig. 3 is an attempt to illustrate the appearance and relation of PSM V22 D308 Head of comet on october 10 1882.jpgFig. 3.—Head of Comet October 10, 1882. things by a mere outline sketch, which, of course, can not be considered in any sense a representation, since it fails entirely to give an idea of the shading and gradation of light. The head of the comet presented no definite outline what-ever, and the nucleus very little. The knots were mere condensations of brightness in the midst of diffuse light. When the dawn came on, the fainter parts successively disappeared, so that at a certain stage the nucleus seemed to be divided into two portions. A small telescope would probably show things in the same way even before dawn, and this is undoubtedly the origin of the reports that the comet had split in two.

This great and unprecedented elongation of the nucleus is a most remarkable phenomenon. If it had occurred at or near the time of perihelion passage, it might have been naturally attributed to the divellent action of the sun's attraction; but it is a little difficult to see why the thing should have pulled out and come to pieces in such a way after getting safely by the crisis. It is worth noting that this peculiarity of the comet adds greatly to the difficulty of making accurate observations of its position: one does not know just upon what point to direct his instrument.

Continuous cloudy weather prevented any observation of the comet until the 15th. On that date the appearance of things as seen in the