Dental Metallurgy: A Manual for the Use of Dental StudentsWhite Mfg. Company, 1882 - 253 páginas |
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Dental Metallurgy: A Manual for the Use of Dental Students (1882) Charles James Essig Sin vista previa disponible - 2008 |
Términos y frases comunes
addition affinity alloy aluminium amalgam amount antimony argentic chloride arsenic artificial dentures bismuth blow-pipe borax brass brittle cadmium carats carbon cent charcoal chemical chloric acid color combination compounds consists constituents containing converted cooling copper counter-die crucible crystals cupel decomposed dental laboratory dentists dentures dilute dissolved ductile dwts employed finely-divided flame fluid foil furnace fused fusible fusing-point fusion grains heated to redness hydrochloric acid hydrogen inches ingot mold iridium iron latter lead malleable mass means melted mercury metal Metallurgy mixed mixture mouth nitrate nitric acid obtained operation ounce oxide oxygen palladium pieces placed plate platinum portion potassium poured powder precipitate present properties proportions pure gold pure silver purple of Cassius readily red heat reduced rendered result salt separated small quantities sodium solder soluble solution specific gravity steel sulphate sulphide sulphuric acid surface teeth temperature tenacity tion tube vessel volatile washed wire zinc
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Página 147 - Let 1,000 be the weight of alloy originally taken ; p the weight of the piece of gold finally obtained ; x the actual amount of gold in the alloy expressed in thousandths; a the weight of gold (supposed to be absolutely pure) taken as a check, which approximately equals x ; b loss or gain in weight experienced by (a) during the process of assay { k variation of
Página 137 - ... composition of which is not definitely known. However, it is supposed by some to be stannous stannic oxide, aurous and auric oxide. As prepared in this manner "Oswald" claims the precipitate to be colloidal gold in stannic acid. The following methods may be used when a quantity of this material is desired: Seven parts of gold are dissolved in aqua regia and mixed with two parts of tin, also dissolved in aqua regia. This solution is largely diluted with water, and a weak solution of one part of...
Página 39 - Let us assume that similar particles of matter attract each other more powerfully than dissimilar ones. It will then follow that the attraction subsisting between the particles of a mixture will be sooner overcome by repulsion than in the case of a homogeneous body ; hence mixtures should fuse more readily than their constituents.
Página 148 - ... p, the weight of the piece of gold finally obtained ; x, the actual amount of gold in the alloy expressed in thousandths ; a, the weight of gold supposed to be absolutely pure taken as a check, which approximately equals x; b, loss or gain in weight experienced by a, during the process ol assay ; k variation of " check gold " from absolute purity, expressed in thousandths.
Página 131 - To reduce gold to a required carat, multiply the weight of gold used by 24 and divide the product by the required carat. The quotient is the weight of the mass when reduced, from which subtract the weight of the gold used, and the remainder is the weight of the alloy to be added.
Página 39 - It is generally admitted that matter in the solid state exhibits excess of attraction over repulsion, while in the liquid state these forces are balanced, and in the gaseous state repulsion predominates over attraction. Let us assume that similar particles of matter attract each other more powerfully than dissimilar ones ; it will then follow that the attraction subsisting between the particles of a mixture will be sooner overcome by repulsion than will the attraction in the case *Makins
Página 75 - As compared with the ordinary gas furnace it appears almost a toy, owing to its great simplicity. The casing holds the heat so perfectly that the most refractory substances can be fused with ease, using a common footblower. Half a pound of cast-iron requires from seven to twelve minutes for perfect fusion, the time depending on...
Página 238 - Bronze is an alloy of copper and tin, and sometimes zinc. It is affected by changes of temperature in a manner precisely the reverse of that in which steel is affected, becoming soft and malleable when quickly cooled, and hard and brittle when allowed to cool slowly. The art of making bronze was practised before any knowledge of the working of iron existed, and it was used at a very early period in the manufacture of weapons. Commercial tin is liable to contain minute quantities of lead, iron, copper,...
Página 100 - ... oxide instead of the free metal is obtained. The reduction of many of this class of ores consists simply in such interchanges. The application of heat and air in some instances converts the sulphide into a sulphate which in turn may be decomposed at high temperatures and separated into sulphur dioxide and a metallic oxide. On the other hand, some of the sulphides may, when heated with access of air, be converted into permanent sulphates capable of resisting high degrees of heat. The sulphides...
Página 148 - check gold " from absolute purity, expressed in thousandths. Then the actual amount of fine gold in the check-piece = A (i— - ). and the corrected weight 1,000 will be x = f -- ^- + 6.