„ sudden outbursts of, 33 Stoney, Dr. G. Johnstone, on the pre-nebular condition of matter, 99 Subaërial denudation, method of estimating rate of, 39, 47 Sun, age of heat of, 34 Sun’s heat, age of, according to Geology, 37 „ age of, a crucial test, 34, 37 Sun’s heat, age of, according to Thomson and Tait, 35 „ age of, as determined by Biology, 64 „ age of, as determined by Geology, 39 Tait, Prof., nebulæ with solid matter in a gaseous mass, 20 „ on age of sun’s heat, 35 Temperature excessive, essential to nebulæ, 26 „ produced by collision, 5 Thomson, Sir W., on age of sun’s heat, 35 „ on meteorites, 12 „ on origin of solar nebula, 28 „ on solar nebula, 6 „ suggestion by, 86 Tides, supposed influence on denudation, 45 Tycho Brahe, on sudden outburst of a star, 33 Tylor, Alfred, on the denudation of Mississippi Basin, 40 Uinta Mountains, denudation of, 58 „ fault in, 57 Vortex atoms, Prof. Lodge on, 88 “Wahsatch Fault,” Utah, immense dislocation, 58 Wallace, Mr. A. R., on geological time, 65, 68 „ method of estimating rate of denudation, 57 Williams, Mr. Mattieu, on universal atmosphere, 86 Winchell, Prof. A., on age of the earth, 64 „ on comets strangers to our system, 17 „ on denudation of Colorado plateau, 58 „ on deposition of Palæozoic sediment, 45 „ on ethereal medium, 87 „ on meteoric origin of nebulæ, 22 „ on nebular hypothesis, 69 „ on the pre-nebular condition of matter, 71 ------------------------------------------------------------------------ _D. APPLETON & CO.’S PUBLICATIONS._ DISCUSSIONS ON CLIMATE AND COSMOLOGY. By JAMES CROLL, LL. D., F. R. S. With Chart. 12mo. Cloth, $2.00. CONTENTS: Misapprehensions regarding the Physical Theory of Secular Changes of Climate.—The Ice of Greenland and the Antarctic Continent not due to Elevation of the Land.—Mr. Alfred R. Wallace’s Modification of the Physical Theory or Secular Changes of Climate.—The Physical Cause of Mild Polar Climates.—Interglacial Periods and Distribution of Flora and Fauna in Arctic Regions.—Temperature of Space and its Bearing on Terrestrial Physics.—Probable Origin and Age of the Sun’s Heat, etc., etc. CLIMATE AND TIME IN THEIR GEOLOGICAL RELATIONS: A THEORY OF SECULAR CHANGES OF THE EARTH’S CLIMATE. By JAMES CROLL, of H. M. Geological Survey of Scotland. With Maps and Illustrations. 12mo. Cloth, $2.50. “I have studiously avoided introducing anything of a hypothetical character. All the conclusions are based on known facts or admitted physical principles. In short, the aim of the work is to prove that secular changes of climate follow, as a necessary effect, from admitted physical agencies, and that these changes, in as far as the past climatic condition of the globe is concerned, fully meet the demand of the geologist.”—_From the Preface._