But the wind slides eastward over its opaque surface in vain, till it reaches the living surface beyond.
They have a semi-opaque body with an "egg-shell" surface and are delicately tinted with colour.
It contains about 20% of cinnamic acid in addition to 18 or even more of benzoic. (3) Palembang benzoin, an inferior variety, said to be obtained from Styrax benzoin in Sumatra, consists of greyish translucent resinous masses, containing small white opaque tears.
But, except perhaps in the case of very fine gratings, it is probable that the error thus caused is insignificant; for the incorrect estimation of the secondary waves will be limited to distances of a few wave-lengths only from the boundary of opaque and transparent parts.
The light stopped by the opaque parts of the grating, together with that distributed in the central image and lateral spectra, ought to make up the brightness that would be found in the central image, were all the apertures transparent.
There are many shades of transparent blue and of opaque blue, yellow and green.
The milk of the cow, which may be taken as typical of all others, and is indeed by far the most important and valuable of all, is, when newly drawn, an opaque white fluid, with a yellowish tinge, soft, bland and sweetish to the taste, and possessed of a faintly animal odour.
It is an ironblack, opaque mineral, with metallic lustre; hardness about 6, sp. gr.
Solid caustic potash forms an opaque, white, stone-like mass of dense granular fracture; specific gravity 2'1.
The nodules from the "blue earth" have to be freed from matrix and divested of their opaque crust, which can be done in revolving barrels containing sand and water.
Long, elliptic-ovate, doubly toothed, pointed, numerously ribbed, hairy below and opaque, and not glossy as in the beech, have short stalks and when young are plaited.
If the bead is coloured we may have present: cobalt, blue to violet; copper, green, blue on cooling; in the reducing flame, red when cold; chromium, green, unaltered in the reducing flame; iron, brownish-red, light-yellow or colourless on cooling; in the reducing flame, red while hot, yellow on cooling, greenish when cold; nickel, reddish to brownish-red, yellow to reddish-yellow or colourless on cooling, unaltered in the reducing flame; bismuth, yellowish-brown, light-yellow or colourless on cooling; in the reducing flame, almost colourless, blackish-grey when cold; silver, light yellowish to opal, somewhat opaque when cold; whitish-grey in the reducing flame; manganese, amethyst red, colourless in the reducing flame.
BALANOGLOSSUS, the general name given to certain peculiar, opaque, worm-like animals which live an obscure life under stones, and burrow in the sand from between tide-marks down to the abyssal regions of the sea.
When light proceeding from a small source falls upon an opaque object, a shadow is cast upon a screen situated behind the obstacle, and this shadow is found to be bordered by alternations of brightness and darkness, known as " diffraction bands."
At other parts of the field the effect is the same, in accordance with the principle known as Babinet's, whether the imaginary screen in front of the object-glass is generally transparent but studded with a number of opaque circular disks, or is generally opaque but perforated with corresponding apertures.
If now we suppose the aperture AB to be covered by a great number of opaque strips or bars of width d, separated by transparent intervals of width a, the condition of things in the directions just spoken of is not materially changed.
The Romans had at their command, of transparent colours, blue, green, purple or amethystine, amber, brown and rose; of opaque colours, white, black, red, blue, yellow, green and orange.
Some coarse kinds are opaque, resembling in this respect jasper, and some writers have sought to restrict the name "bloodstone" to green jasper, with red markings, thus making heliotrope a translucent and bloodstone an opaque stone, but, though convenient, such a distinction is not generally recognized.
It is opaque, except in exceedingly thin slices, such as made for microscopic investigation, which are imperfectly transparent, and of a dark brown colour by transmitted light.
Hull published accounts of an exact and extensive research, in which the principle had been fully and precisely confirmed as regards both transparent and opaque bodies.
They should be so erected as to present the smallest extent of opaque surface consistent with stability.
Carbonado or " black diamond," found in Bahia (also recently in Minas Geraes), is a black material with a minutely crystalline structure somewhat porous, opaque, resembling charcoal in appearance, devoid of cleavage, rather harder than diamond, but of less specific gravity; it sometimes displays a rude cubic crystalline form.
True amber yields on dry distillation succinic acid, the proportion varying from about 3 to 8%, and being greatest in the pale opaque or "bony" varieties.
Glessite, a nearly opaque brown resin, with numerous microscopic cavities and dusty enclosures, named from glesum, an old name for amber.
The different kinds of mica vary from perfectly colourless and transparent - as in muscovite - through shades of yellow, green, red and brown to black and opaque - as in lepidomelane; the former have a pearly lustre and the latter a submetallic lustre on the cleavage surfaces.
The least wind raises clouds of fine dust, which fill the air, render it so opaque as to obscure the noonday sun, and make respiration difficult.
By the aid of photography it is easy to prepare a plate, transparent where the zones of odd order fall, and opaque where those of even order fall.
If the grating be composed of alternate transparent and opaque parts, the question may be treated by means of the general integrals (§ 3) by merely limiting the integration to the transparent parts of the aperture.
We have now to consider the amplitude due to a single element, which we may conveniently regard as composed of a transparent part a bounded by two opaque parts of width id.
We conclude that, with a grating composed of transparent and opaque parts, the utmost light obtainable in any one spectrum is in the first, and there amounts to I/wr 2, or about 6, and that for this purpose W a and d must be equal.
Babinet, the brightness of a lateral spectrum is not affected by an interchange of the transparent and opaque parts of the grating.
The usual process was to gather, first, a small quantity of opaque white glass; to coat this with a thick layer of translucent blue glass; and, finally, to cover the blue glass with a coating of the white glass.
Fresnel commenced his researches with an examination of the fringes, external and internal, which accompany the shadow of a narrow opaque strip, such as a wire.
It forms colourless transparent crystals, soluble in one and a half parts of cold water and in eight parts of alcohol, which on exposure to ordinary air become opaque through absorption of carbonic acid, which forms a crust of basic carbonate.