They pass through a viscous stage in cooling from a state of fluidity; they develop effects of colour when the glass mixtures are fused with certain metallic oxides; they are, when cold, bad conductors both of electricity and heat, they are easily fractured by a blow or shock and show a conchoidal fracture; they are but slightly affected by ordinary solvents, but are readily attacked by hydrofluoric acid.
Calcium carbide, as formed in the electric furnace, is a beautiful crystalline semi-metallic solid, having a density of 2.22, and showing a fracture which is often shot with iridescent "non-automatic."
Wrought iron and mild steel may be made to show a short and crystalline fracture by a sudden application of stress, while if drawn asunder slowly they develop the silky, fibrous appearance.
When this has been done an electrical test is applied, and if the original fracture is between ship and shore the heaving in of cable will continue until the end comes on board.
Bismuth is a very brittle metal with a white crystalline fracture and a characteristic reddish-white colour.
The surface of the vessel may be hard, but the vessel is liable to fracture on receiving a trifling shock.
Formerly, on the eve of a great eruption of Mauna Loa, this crater often spouted forth great columns of flame and emitted clouds of vapour, but in modern times this action has usually been followed by a fracture of the mountain side from the summit down to a point moo ft.
The Indo-Gangetic depression was formed by the weight of the over-riding mass bending down the edge over which it rode, or else it is the lower limb of the S-shaped fold which would necessarily result if there were no fracture - the Himalaya representing the upper limb of the S.
The chemical composition of typical obsidians is shown by the following analyses Obsidian, when broken, shows a conchoidal fracture, like that of glass, and yields sharp-edged fragments, which have been used in many localities as arrow-points, spear-heads, knives and razors.
At this neck-like zone the muscles are absent, and across it falls the line of fracture when the proglottis separates from its fellows.
The product has a brilliant white fracture, a specific gravity of 4.87, very friable, but harder than quartz or steel.
Half of Molokai, there is evidence of a fracture followed by the submergence of a portion of a volcano.
Hence the weakness and the dark-grey fracture of this iron, and hence, by brushing this fracture with a wire brush and so detaching these loosely clinging flakes of graphite, the colour can be changed nearly to the very light-grey of pure iron.
Wide were jumped downward from it in the intended plane; this prevented a skew fracture (PT.
It is then examined by a native expert (purkhea) as to impurities, colour, fracture, aroma and consistence.
All soundings exceeding 4000 fathoms, occur in trenches, and there are only a few small trenches known (on the west coast of Central America) in which the maximum depth is less than 3000 fathoms. Jlost trenches are narrow, but of considerable length, and their steeper side is believed to be due in every case to a great fracture of the earth's crust..
The transverse fracture has a resinous appearance with white streaks; the flavour is bitter and aromatic, and the odour characteristic. It consists of a mixture of resin, gum and essential oil, the resin being present to the extent of 25 to 40%, with 21to 8% of the oil, myrrhol, to which the odour is due.
Thus, prior exposure to a temperature materially above Ac 3 coarsens the structure of most steel, in the sense of giving it, when cold a coarse fracture, and enlarging the grains of pearlite, &c., later found in the slowly cooled metal.
- In common practice the cast iron as it runs from the blast-furnace is allowed to solidify and cool completely in the form of pigs, which are then graded by their fracture, and remelted in the puddling furnace itself.
Diamond may break with a conchoidal fracture, but the crystals always cleave readily along planes parallel to the octahedron faces: of this property the diamond cutters avail themselves when reducing the stone to the most convenient form for cutting; a sawing process, has, however, now been introduced, which is preferable to that of cleavage.
The mineral is also frequently found massive, with a coarse or fine granular structure and a crystalline fracture; sometimes it occurs as a soft, white, amorphous deposit resembling artificially precipitated zinc sulphide.
A brittle potassium alloy of silver-white colour and lamellar fracture is obtained by calcining 20 parts of bismuth with 16 of cream of tartar at a strong red heat.
It is unnecessary here to rake among the ashes of this prolonged dispute, but it may be noted that Helmholtz, who, in his lecture on "Ice and Glaciers," adopted Thomson's theory, afterwards added in an appendix that he had come to the conclusion that Tyndall had "assigned the essential and principal cause of glacier motion in referring it to fracture and regelation" (1865).
In case of direct puddling and the use of larger charges this conservatism has some foundation, because the established custom of allowing the cast iron to solidify gives a better opportunity of examining its fracture, and thus of rejecting unsuitable iron, than is afforded in direct puddling.
By modern mineralogists the name chalcedony is restricted to those kinds of silica which occur not in distinct crystals like ordinary quartz, but in concretionary, mammillated or stalactitic forms, which break with a fine splintery fracture, and display a delicate fibrous structure.
The ductile metals and alloys also extend from Jo to 30 with reduction of area before they fracture, the crystalline ones snap shortly without warning.
This is effected by stirring the molten metal with a pole of green wood (" poling "); the products which arise from the combustion and distillation of the wood reduce the oxide to metal, and if the operation be properly conducted " tough-pitch " copper, soft, malleable and exhibiting a lustrous silky fracture, is obtained.
Overlooking all smaller details, we may consider Asia to consist of a northern mass and a southern mass, too rigid to crumple, but not too strong to fracture, and an intermediate belt of softer rock which was capable of folding.
When, the region was broken into fault blocks and the blocks were uplifted and tilted, the back slope of each block was a part of the previously eroded surface and the face of the block was a surface of fracture; the present form of the higher blocks is more or less affected by erosion since faulting, while many of the lower blocks have been buried under the waste of the higher ones.
A typical resin is a transparent or translucent mass, with a vitreous fracture and a faintly yellow or brown colour, inodorous or having only a slight turpentine odour and taste.
Frequent annealings are necessary to prevent fracture of the metal; but with these and the observance of certain other precautions of a practical character the degree of extension possible is enormous.