History of Helianthus tuberosus.... Living and Fossil Oaks of Europe.. The Effect of Frost on Chlorophyl Granules. Effect of Frost on Evergreen Leaves... History and Uses of Jaborandi.. AGRICULTURE AND RURAL ECONOMY. By Professor W. 0. Ar- WATER, Wesleyan University, Middletown, Conn..... AGRICULTURAL EXPERIMENT STATIONS.. Growth of the Experiment Stations..... Resources, Appliances, and Work of the Experiment Stations.. 350 THE ATMOSPHERE AS RELATED TO VEGETATION. Nitrogen Compounds Brought to Soil by Snow... Influence of Forests upon Rainfall and Temperature... THE SOIL IN ITS RELATIONS TO VEGETABLE PRODUCTION Percolation of Water through the Soil, and Consequent Loss of Loss of Plant-Food through Rivers.. The Causes of Soil-Absorption.. The Absorption of Bases by the Soil... Oxidation of Nitrogen Compounds in the Soil. SOURCES AND FUNCTIONS OF INGREDIENTS OF PLANT-FOOD...... The Sources of the Nitrogen of Vegetation...... Sources of Nitrogen Removed from the Soil by Crops without Ni- Assimilation of Nitrogen by Leguminous Crops Aided by Potassic Is the Free Nitrogen of the Air a Source of the Nitrogen Assimi- Is the Combined Nitrogen of the Air the Source of the Assimilated Nitrification by Electrical Discharges.. Is the Nitrogen Combined under the Influence of the Soil a Source of the Supply Assimilated by Plants ?... Best Forms of Nitrogen for Plant-Food. Source of the Carbon of Plants... Root-DEVELOPMENT OF PLANTS..., The Need of Better Information about Fertilizers . Fodder Corn and Sweet-Potatoes. Pumpkins, Squashes, Broom-Corn Seeds, Weeds, etc Sugar-Beet Culture and Beet-Sugar Making. NUTRITION OF ANIMALS.-STOCK-FEEDING.. Sources of the Fat of the Animal Body... Effect of Fodder upon Milk Production.. Changes in the Milk during the Period of Lactation... GENERAL CONCLUSIONS FROM EXPERIMENTS ON EFFECTS OF FOOD The Digestive Capacity of Horses.. Digestion of Foods by Swine.... Digestion of Foods by Sheep.... Value of Animal Waste as Food for Stock.–Fish-Scrap. RAILROADS..... The CANAL ACROSS THE AMERICAN ISTHMUS. THE MISSISSIPPI JETTIES.. OTHER AMERICAN ENGINEERING WORKS. 381 382 383 384 IMPROVEMENT ON THE UPPER MISSISSIPPI. THE MADEIRA AND MANORÉ RAILWAY TECHNOLOGY. By William H. Wahl, Ph.D., Philadelphia, Pa....... 395 COMPARISON OF A COAL-FURNACE AND A SIEMENS GAS-FURNACE IN THE MANUFACTURE OF PLATE-GLASS.. UTILIZATION OF BLAST-FURNACE SLAG.. INDUSTRIAL STATISTICS. By WILLIAM H. Wahl, Ph.D., Philadel- PRODUCTION OF PIG-IRON IN 1876... CONDITION OF BLAST-FURNACES OCTOBER 1, 1877.. THE COMPARATIVE PRODUCT OF PIG-IRON BY STATES. PRODUCTION OF ROLLED IRON IN 1876.. STEEL PRODUCTION OTHER THAN BESSEMER........ PRODUCTION OF IRON AND STEEL BY THE OPEN-HEARTH PROC 3.. 410 THE PRODUCT OF THE FORGES AND BLOOMERIES....... GENERAL ANALYSIS OF Total IRON AND STEEL PRODUCTION. 411 THE IRON TRADE OF THE UNITED STATES IN 1877.. INTRODUCTION. The year 1877 will be remembered by the discovery of the two faint satellites of Mars more than by any other one event. A possible satellite of Mars has often been sought for by D'Arrest, Tuttle, and others, but an imagined analogy placed such a satellite or satellites farther from the planet than either of the bodies discovered by Professor Hall. These satellites may be said to be fatal to the analogies ordinarily quoted, and to show how vague a guide these really are. The outer satellite is almost unique in the solar system, and the inner one is quite so, in its relations of distance and mass with its primary. A further account of these will be found in the proper place. The changes of spectrum of Schmidt's Nova Cygni are of great importance, and are certainly not yet understood; and the same may be said of Dr. Henry Draper's discovery of oxygen in the sun, even the nearer consequences of which have not yet been worked out. A The astronomical expedition of Mr. David Gill to Ascension Island is particularly noteworthy; and by advices from Mr. Gill up to October 8, it appears probable that success is secured. These and other subjects are spoken of briefly under their appropriate heads, but it must be remembered that the accounts here given are necessarily the barest summaries, and are intended mainly to call attention to work which has been done, in order that a reference to the originals may be made when desired. NEBULÆ AND THE NEBULAR HYPOTHESIS. Lord Rosse is preparing for publication all the observations of nebulæ made at Birr Castle with his six and three feet mirrors during the last thirty years. Those drawings which have already been published in the Philosophical Transactions will not be republished. The whole will probably be divided into three or four parts, each comprising 6 h. or 8 h. of right ascension. The editing is done by Dr. Dreyer, Lord Rosse's assistant, and the work is to be published by the Royal Irish Academy. It is expected to be soon in the hands of astronomers. Dr. Dreyer is also engaged in preparing a supplement to Herschel's general catalogue of nebulæ, etc., and any additions or corrections to this should be sent to him. The Melbourne reflector has for some time been employed for the purpose of re-drawing all nebulæ previously figured by Sir John Herschel Forty-nine nebulæ have been carefully drawn by the observers, and the results of the work are about to be published. Mr. Ellery speaks of the lithographic copies of these drawings as fully successful. M. Stephan, of Marseilles, gives the places of thirty new nebulæ discovered by him, making 185 in all found at Marseilles. The first 125 of these will appear in Dreyer's new catalogue of nebulæ. Dr. Koch, of the Leipzig Observatory, has published a micrometric investigation of the cluster G. C. 1712 for his inaugural dissertation. It contains an interesting résumé of previous work of this kind. Other work of the kind is now in hand at this observatory. The cluster Gamma Argūs, respecting which Gilliss reported changes since Sir John Herschel's observations, has |