CONTENTS. Mineral, rock, and ore analyses.... Gahnite, from Montgomery County, Maryland Alum rock, from Grant County, New Mexico.... Scoriaceous Obsidian, from Mono Valley, California.. Limestones, from Moundsville, West Virginia.... Magnetite, from near Bozeman, Montana ... Limonite, from Canaan Mountain, West Virginia.. Hot Spring, foot of Granite Mountain, Nevada....... Hot Spring, Hot Spring Station, Nevada.. Larger Soda Lake, Ragtown, Nevada.. Spring on Tufa Crag in Mono Lake, California.... Warm Spring, Mono Basin, California Livingston Warm Springs, Montana Warm Springs, Emigrant Gulch, Montana. Helena Hot Springs, Montana....... Mill Creek Cold Spring, Montana........ Paga 18 18 INTRODUCTORY. The present bulletin contains the more important results obtained in the chemical laboratory of the United States Geological Survey at Washington, between December 12, 1883, and June 30, 1884. The work here reported was almost wholly done by Dr. T. M. Chatard and myself, and represents the first fiscal year of our laboratory organization. Other work, carried forward in this laboratory by Dr. F. A. Gooch, and relating mainly to the rocks and waters of the Yellowstone National Park, is reserved for a future bulletin. In addition to the analyses here published, a considerable number of assays, mineral determinations, and qualitative examinations have been made. Several researches have also been begun, but are not yet advanced enough to warrant any announcement. Other bulletins will be issued from time to time, as fast as material accumulates. WORK DONE IN THE WASHINGTON LABORATORY DURING THE FISCAL YEAR 1883--'84. MINERAL, ROCK, AND ORE ANALYSES. The mineralogical work of the division of chemistry has been done in close co-operation with the mineral department of the National Museum. Some of the material studied has been received through the latter institution; some has been brought in by field parties of the Survey; some represents our own summer collecting. The rocks, clays, etc., analyzed, have been submitted by other divisions of the survey, and will not be specially discussed in this bulletin. The only novelty in the methods of analysis has been in the use of the bismuth oxide process for the estimation of the alkalies in silicates. This process, as modified by Dr. Chatard, is described later. GAHNITE FROM GILMORE'S MICA MINE, MOUNTGOMERY COUNTY, MARYLAND. The locality at which this mineral was found is 12 miles north of Washington, near Colesville, Maryland. The mine has yielded a considerable quantity of merchantable mica, which occurs in the usual granite vein, associated with quartz, albite, garnet, black tourmaline, and beryl. The last-named mineral is abundant in large but ill-formed crystals. But one specimen of the gahnite was obtained; a dark-green massive specimen, filling a cavity in altered feldspar. Specific gravity 4.59. Analysis by T. M. Chatard: Among the Eskimo implements collected by the U. S. Signal Service at Point Barrow, Alaska, were a considerable number of a material which appeared to be jade. Of these there were two varieties; one pale apple-green, the other dark-green; both were highly polished, and exceedingly compact and tough. The specific gravity of the pale-green |