Page:Popular Science Monthly Volume 19.djvu/731

Rh including the tube, polar and declination axes, counterpoise, and various adjustments, weigh altogether between six and seven tons, yet the whole apparatus is under such control that one person can move it about and manipulate it with ease. The motion on the axes has been facilitated by the application of antifriction apparatus to them, so that it has not been necessary to make them disproportionately small, as has been the case with the axes of previous large instruments. The circles are carefully and accurately divided on a band of gold, and so adjusted and illuminated that the observer can, without stirring from his chair, read all of the circles of the instrument through a single reader-telescope attached to the side of the main tube. The builder of the instrument had great difficulty in obtaining perfect glass for the objectives, and more than a year, from October, 1879, to December, 1880, was spent in trying to produce a good lens; nevertheless the instrument was completed in less than half the time stipulated for by the Austro-Hungarian Government. The observatory in which the telescope is to be placed is an imposing edifice of three hundred and forty by two hundred and forty feet, and stands at an elevation of two hundred feet above the city, upon grounds of between fifteen and sixteen acres in extent.

The Cave-Temples of India.—Dr. James Fergusson's recent work on the "Cave Temples of India" abounds in illustrations of the manner in which the art of building in stone has been developed from wooden construction. The beginning of the use of stone in India is fixed, in Dr. Fergusson's opinion, at the period of the reign of Asoka, 250, for no stone buildings of an architectural character have been found the date of which can be proved to be earlier than that of this monarch. Moreover, all the older examples are, in all their details, so clearly copies of original types in wood, that it is improbable that they could have been executed by a people who had any previous knowledge of the principles of stone architecture. All caves, down to the seventh century, show the gradual transformation from wooden forms into those of stone. The modifications may be traced onward through nine centuries—all that was of stone being copied literally from carpentry forms, till the process was nearly complete, and forms, originally distinctly wooden, had become appropriated to stone architecture. All this seems to have been effected without any direct foreign influence. The earlier caves are adorned with sculptures in preference to painted figures, but the later ones are covered with paintings of a high order of art and great historical interest, with colors perfectly fresh, while sculpture, where it occurs at all, occupies a subordinate position. No figure of Buddha occurs before the end of the first century. The liturgical forms, in all the older caves, express a simple but exclusive type of relic-worship. About one thousand distinct caves in India are mentioned as having architectural importance, of which three fourths belong to the Buddhists, one fifth to the Brahmans, and five per cent, to the Jains. The Buddhist caves are the oldest and the most interesting. They are all true caves, excavated at right angles to the face of the rock in which they are formed, with designs appropriate to their situation in it. The caves of the Brahmans are often copies of structures whose outlines have no reference to the position in which they are placed, or the material out of which they are carved. The Buddhist caves seem to have been gradually developed from single plain cells cut into the rock, the dwelling of a single anchorite, into groups of eighteen or twenty cells, arranged around a hall sixty or seventy feet square, the roof of which was supported by pillars elaborately carved, the whole forming a vihara or monastery. Such caves are usually found grouped together, five or ten, and even fifty or sixty in immediate juxtaposition, so as to form an establishment capable of accommodating a large number of monks. To each of the groups was attached one or more chaityas or "church-caves," as they might be called, which were analogous in form and use to the choirs in Christian churches. The finest of these is that of Carlee, near Poonah.

Lunar "Craters."—M. Faye recently delivered a lecture at the Sorbonne, on the volcanoes of the moon, the substance of which was an essay to show that there are