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Abbe condenser acetate adjustment ammonium hydroxide amorphous angle appear barium bichromate calcium cell cesium cesium chloride chemical chloride chromate color compound concentrated condenser copper cover-glass cross-hairs Crystal Forms crystalline decant diameter diaphragm dilute disk dissolved employed evaporate examination eyepiece fibers focus fragment glass heating Hexagonal hydrochloric acid instrument iodide lamp lens light rays liquid magnesium magnification material means mercuric metal method micro microchemical micrometer microscope millimeters mirror mixtures monoclinic mounting nicols nitrate nitric acid numerical aperture object slide oblique obtained ocular ocular scale optic axis Orthorhombic oxalate particles phosphate placed plane plate platinum polarized potassium precipitate preparation present prisms radiant reaction reagent reflected refractive index removed salts scale screw separate shown in Fig silver silver nitrate sodium soluble solution specimen stage strontium substage substance sulphate sulphuric acid surface test drop thickness thin thiocyanate tiny tion Triclinic tube ultramicroscope usually vertical illuminators yield zinc
Page 30 - ... inclined at an angle of forty-five degrees with the elevation of the object ; then it is plain, that since the angle of reflection is equal to the angle of incidence, the greatest part of the rays which fall upon the horizon will...
Page 5 - Dry objectives may be compared with each other with reference to their angular aperture. In general the angular aperture depends largely upon the diameter of the front combination of the objective, and usually in objectives of like magnifying power, the greater this diameter the larger will be the angular aperture and the wider and clearer will be the area or field covered. It is also generally true that the shorter the equivalent focus of the objective, the larger its angular aperture and that dry...
Page 48 - ... color. The object will then appear strongly illuminated, but colored upon a colored background. If, for example, the central disk is blue and the ring red, the objects will appear red upon a blue background. With care and a suitable choice of colors, very remarkable results may be obtained which may greatly facilitate the study of certain sorts of material. In this connection it may be pertinent to point out that the illumination of opaque objects (and transparent objects as well) by monochromatic...
Page 214 - Tube 1 . . Tube 2 .... Tube 3 Tube 4 Tube 5 Tube 6 Tube 7 Tube 8 Concentration of Standard in gram -molecules.
Page 103 - The development of microscopic methods for the study and identification of opaque minerals ' within the last few years has created a demand for inexpensive, easily transportable instruments of simple construction which may be carried and used in the field. A microscope of this sort was described by Davy at the August, 1920, meeting of the American Institute of Mining and Metallurgical Engineers.
Page 4 - This position of the standard mark permits lengthening or shortening the draw-tube, and thus correcting for cover-glass thickness as stated above. In addition to corrections for chromatic and spherical aberration at least two other factors must be taken into account in comparing, or choosing between, objectives of similar equivalent focal length. These are the angular aperture and the numerical . , aperture of the objectives. By the angular aperture of an objective is meant the " angle contained,...
Page 350 - H2O, which crystallizes in stout monoclinic prisms somewhat resembling the short, thin prisms of calcium sulphate. Strontium and barium prevent the formation of the double salt. Elements of the magnesium group interfere. Lithium likewise interferes. But the chlorides of iron and aluminum and the salts of boric acid have no appreciable effect on the reaction. When in doubt as to the nature of a precipitate formed by the treatment with HNaCO3...