Transcriber’s note: Table of Contents added by Transcriber. Bold text is indicated with =equals signs=, italics with _underscores_. CONTENTS Advance of Astronomy During the Nineteenth Century 289 The Applications of Explosives 300 A Paradoxical Anarchist 312 What Makes the Trolley Car Go 316 Woman’s Struggle For Liberty in Germany 328 Scenes on the Planets 337 Professor Ward on “Naturalism and Agnosticism” 349 Destructive Effects of Vagrant Electricity 357 Winter Birds in a City Park 366 Old Rattler and the King Snake 371 Remarkable Volcanic Eruptions in the Philippines 374 The Scavengers of the Body 379 Editor’s Table 385 Fragments of Science 388 Minor Paragraphs 395 Publications Received 399 Established by Edward L. Youmans APPLETONS’ POPULAR SCIENCE MONTHLY EDITED BY WILLIAM JAY YOUMANS VOL. LVI NOVEMBER, 1899, TO APRIL, 1900 NEW YORK D. APPLETON AND COMPANY 1900 COPYRIGHT, 1900, BY D. APPLETON AND COMPANY. APPLETONS’ POPULAR SCIENCE MONTHLY. JANUARY, 1900. ADVANCE OF ASTRONOMY DURING THE NINETEENTH CENTURY. BY SIR ROBERT BALL, LOWNDEAN PROFESSOR OF ASTRONOMY AT THE UNIVERSITY OF CAMBRIDGE, ENGLAND. One of the most remarkable chapters in the astronomy of the past century was commenced on the very first night with which that century began. It was, indeed, on the 1st of January, 1801, that the discovery of a new planet was announced. The five great orbs--Jupiter, Saturn, Mercury, Mars, and Venus--had been known from the earliest times of which we have records, and the planet Uranus had been discovered nearly twenty years before the previous century closed. The solar system was thus thought to consist of these six planets and, of course, the earth. On the memorable night to which I have referred, Piazzi, the astronomer, made a remarkable advance. He discovered yet another planet--the seventh, or eighth, if the earth be included. The new body was a small object in comparison with those which were previously known. It was invisible to the unaided eye, and seemed no more than a starlike point even when viewed through a telescope. It revolved around the sun in the wide region between the orbits of Mars and Jupiter. This discovery was speedily followed by others of the same kind, and, as the century has advanced to its close, the numbers of these planets--asteroids, as they are generally called--has been gradually increasing, so much so that now, of these little bodies known to astronomers, the number amounts to about four hundred and fifty.