The American Journal of Science, Band 160J.D. & E.S. Dana, 1900 |
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acetylene amount analysis appears atoms Backii beds biotite bolometer bulb calcite carbonate Carex carnotite cathode cathode stream cent chloride cm³ coil color composition condenser containing copper corundum crystals curve Cycadeoidea deflection deposits described determined diameter dike dilute domeykite electric absorption element experiments feldspar formula Geological given glass gram H₂O heat hydrochloric acid hydrocyanic acid hydrogen iodine iron length lower magnetic material measured mestome-bundles metal method mineral monazite muscovite nearly nitric acid observed obtained occurs oxalic oxalic acid oxide paper particles Phyllostachys plagioclase plate platinum portion posterior potassium precipitate present pressure quartz ratio region residue resistance rhombohedron rock roscoelite sandstone scapolite schists SCI.-FOURTH SERIES silver solution species specimens spectrum structure sulphocyanide sulphuric surface sylvanite Table temperature thermo-element thick thiosulphate tion titration tourmaline tube twinning upper uranium vanadium volume whorl wire X-light
Beliebte Passagen
Seite 170 - The object of the present work is to insist on a directly contrary proposition, namely, that science is in reality a classification and analysis of the contents of the mind ; and the scientific method consists in drawing just comparisons and inferences from the stored impresses of past sense-impressions, and from the conceptions based upon them. Not till the immediate sense-impression has reached the level of a conception, or at least a perception, does it become material for science. In truth, the...
Seite 144 - The body called carnotite is probably a mixture of minerals of which analysis fails to reveal the exact nature. Instead of being the pure uranyl-potassium vanadate, it is to a large extent made up of calcium and barium compounds. Intimately mixed with and entirely obscured by it is an amorphous substance — a silicate or mixture of silicates — containing vanadium in the trivaleut state, probably replacing aluminum.
Seite 453 - ... of water and silver nitrate added in excess. The precipitate was collected upon asbestos in a platinum crucible, washed with cold water and dried to a constant weight at 115° the drying requiring usually between two and three hours. The filtering is facilitated by allowing a few hours for the precipitate to settle ; but this is by no means essential, as it is easy with a little care to obtain a clear filtrate even when the filtering is performed at once. The solution of ammonium sulphocyanide...
Seite 320 - Ward, LF 1900. Status of the Mesozoic floras of the United States. First paper: The older Mesozoic. US Geol. Surv., 2Oth Ann.
Seite 129 - ... would show if it could be followed inward from the surface. A few hundred pounds of picked carnotite ore has been shipped from this claim and is reported to have sold for $1.25 a pound in Denver. This deposit is similar in character to others examined, except that in this case a well-defined fault has provided a zone of crushed and porous rock in the hanging wall, along which impregnation could take place. A few hundred feet farther west the crushed sandstone adjoining the fault has been impregnated"...
Seite 134 - ... particles without crystal outlines and acting so faintly on polarized light as to at first seem almost amorphous. Much of the matter appears merely as a fine brownish clay, stained yellow by an amorphous pigment, but occasionally a well-defined fragment of a light-yellow translucent mineral is seen, which doubtless represents the vanadium compound in its condition of ideal purity. Working over a considerable amount of the powder I have found occasional clusters of this yellow mineral in the form...
Seite 152 - ... acid, after neutralizing with acid potassium carbonate. If the former alternative is followed, the end-reaction must be the disappearance of the yellow color of the iodine, since in solutions so strongly acid it is impossible to place dependence upon the starch indicator; in using the latter alternative, the starch indicator is, of course, permissible and preferable. In the direct titration of...
Seite 450 - ... has never come into general use. The chief reason for this has apparently been the difficulty and inaccuracy attendant upon the weighing of the precipitate upon dried paper filters, a process which can hardly be depended upon unless managed with extreme care. In the experiments to be described this difficulty was avoided by performing the filtering and weighing upon asbestos in a perforated platinum crucible. The method of conducting a determination was as follows : A suitable quantity of a standard...
Seite 450 - ... conducting a determination was as follows : A suitable quantity of a standard copper sulphate solution was run from a burette, diluted to a convenient volume, a few cubic centimeters of a saturated solution of ammonium bisulphite added, and the copper precipitated by an excess of ammonium sulphocyanide. The precipitate was allowed to settle, collected upon asbestos in a weighed crucible, washed with cold water, and dried at 110° until no further loss of weight took place. In Table I are given...
Seite 129 - ... district, but I have no personal knowledge of these occurrences. It seems highly probable that the material will be found widely distributed in the Mesozoic sandstones of western Colorado and eastern Utah, although perhaps nowhere in very extensive bodies. ORIGIN OF THE DEPOSITS. That the bodies of carnotite and roscoelite were formed subsequently to the deposition of the sandstones is evident from the facts presented in the preceding pages. It is equally plain that the minerals could not have...