Bulletin, Ausgaben 303-308

U.S. Government Printing Office, 1907

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Seite vi - PP 55. Ore deposits of the Silver Peak quadrangle, Nevada, by JE Spurr. 1906. 174 pp., 24 pis. B 289. A reconnaissance of the Matanuska coal field, Alaska, in 1905, by GC Martin. 1906.
Seite i - ... publications of the United States Geological Survey consist of (1) Annual Reports, (2) Monographs, (3) Professional Papers, (4) Bulletins, (5) Mineral Resources, (6) Water-Supply and Irrigation Papers, (7) Topographic Atlas of United States — folios and separate sheets thereof, (8) Geologic Atlas of the United States — folios thereof.
Seite 51 - On deck protected" the cylinders shall be protected from the direct rays of the sun by means of structural erections or awnings. Tarpaulins covering cylinders and in contact therewith are not considered adequate protection. Protection by use of wood dunnage Is permitted. [CQFR 53-54, 18 FR 8239. Dec. 16, 1953] § 146.24-35 "Under deck" stowage. (a) Cylinders stowed "Under deck...
Seite 163 - OF SOLUBLE SILICA. Very often in treatment by acids silica is separated in gelatinous or granular form mixed with the unattacked minerals, and it becomes necessary to remove or estimate this silica, or else to discriminate between soluble and insoluble silica already existing together. Usually a boiling solution of sodium carbonate has been employed for this purpose, though the caustic alkalies have found advocates.
Seite 107 - ... on ignition. If an excess of acetic acid has been used, this is cautiously removed by ammonia. Then a drop or two of solution of ammonium oxalate is added, and the small beaker is set aside for twelve hours if necessary. Almost invariably a small precipitate soon shows itself, which, if fine grained and nonadherent to the glass, may be regarded as pure calcium oxalate; otherwise it contains, or may largely consist of, magnesium oxalate. It is in that case to be collected, ignited, redissolved,...
Seite 156 - It is an exceptional case when there is exact agreement between the weight of fluoride and sulphate, and with the small amounts usually met in rocks the error may be an appreciable one in percentage of fluorine, though of no great significance otherwise.
Seite 37 - C. for some hours to certainly expel all absorbed water, and weighed after prolonged cooling in the desiccator. It is better to ascertain the weight of the dry rock after soaking in water than before, in order to avoid the error due to possible breaking off of a few grains between the two weighings. Should the density of the rock in air-dry condition be required, it may be left exposed to the air for a long period after drying and before weighing;1 but the difference will only 4n view of the uncertainty...
Seite 50 - Friedel (loc. cit.) indicates a means for determining the true weight of water lost by minerals behaving like the zeolites, even without collecting the water lost, namely, by driving out of the dehydrated and weighed mineral, under proper precautions, any air it may have absorbed in the process of drying and cooling, and collecting and measuring this air and thus finding its weight, which, added to the apparent loss, gives the true contents in water.
Seite 162 - ... will not alter the general result. Its amount was sometimes readily determinable by Nesslerization, being as high as 0.04 per cent in some slates. Carbonaceous organic matter was absent from most of these, but doubtless existed in them in their early history. In their case the ammonia was, in part at least, evolved as such, imparting a strong alkaline reaction to the water in the upper part of the tube. The presence of sulphides, fluorides, or chlorides in the rock might cause the ammonia to...
Seite 40 - Penfield c recommends the following modification of the suspension method as more convenient than that by the pycnometer in many cases for small fragments of minerals. After boiling in water, the substance is transferred with water to a small glass tube about 8 by 35 mm., provided with a fine platinum wire for suspension. This is weighed full of water in another vessel of water, and again after the removal of the mineral, the weight of which is found after drying. This method is, of course, more...

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