- The state's great mineral wealth is in coals of various kinds, petroleum, and natural gas.
The Ecca shales contain some of the best coals of South Africa, but the seams contain much unmarketable coal.
His jaws worked and his eyes were so dark they were like two coals in a burning face.
The fire ebbed to glowing coals in the silent old building and she snuggled against him.
Outside the customs union (Zollverein), the imports being principally coals, bricks and timber, and the exports fish.
The price of coals at Darlington fell from 18s.
Coals vary much in calorific value, some producing only 12,000 B.Th.U.
They yield valuable coals, clays, marls and ganister.
They yield valuable coals, clays, marls and ganister.
Coals are extracted at Neudorf, Lesitz, Ratiskowitz and Ceic; lignite at Rossitz, Oslavan and Mahrisch-Ostrau.
But the value of the protectorate depends upon the carrying trade with Harrar and the supplying of victuals and coals to French warships.
The stories of a scorpion stinging itself to death when placed in a circle of burning coals are due to erroneous observation.
Around Dundee and Newcastle the coals are bituminous.
In the 15th and 16th centuries the town was a leading seat of the salt industry ("salt to Dysart" was the equivalent of "coals to Newcastle"), but the salt-pans have been abandoned for a considerable period.
A handful of it was also burnt once a year in the Holy of Holies by the high priest on a pan of burning coals taken from the altar of burnt-offering (Lev.
The clay is dug from the land or from ditches or pits and placed in heaps of 60 to ioo loads each, with faggot wood, refuse coals or other fuel.
The plural, coals, seems to have been used from a very early period to signify the broken fragments of the mineral as prepared for use.
The maximum hardness is from 2.5 to 3 in anthracite and hard bituminous coals, but considerably less in lignites, which are nearly as soft as rotten wood.
Coal is never definitely crystalline, the nearest approach to such a structure being a compound fibrous grouping resembling that of gypsum or arragonite, which occurs in some of the steam coals of South Wales, and is locally known as " cone in cone," but no definite form or arrangement can be made out of the fibres.
There is generally a tendency in coals towards cleaving into cubical or prismatic blocks, but sometimes the cohesion between the particles is so feeble that the mass breaks up into dust when struck.
As the amount of ash varies very considerably in different coals, and stands in no relation to the proportion of the other constituents, it is necessary in forming a chemical classification to compute the results of analysis after deduction of the ash and hygroscopic water.
The most important class of coals is that generally known as bituminous, from their property of softening or undergoing an apparent fusion when heated to a temperature far below that at which actual combustion takes place.
That nothing analogous to bitumen exists in coals is proved by the fact that the ordinary solvents for bituminous substances, such as bisulphide of carbon and benzol, have no effect upon them, as would be the case if they contained bitumen soluble in these re-agents.
The proportion of carbon in bituminous coals may vary from 80 to 90% the amount being highest as they approach the character of anthracite, and least in those which are nearest to lignites.
Thus the semi 'anthracitic coals of South Wales are known as " dry " or " steam coals," being especially valuable for use in marine steam-boilers, as they burn more readily than anthracite and with a larger amount of flame, while giving out a great amount of heat, and practically without producing smoke.
Coals richer in hydrogen, on the other hand, are more useful for burning in open fires - smiths' forges and furnaces - where a long flame is required.
The proportion of this residue is greatest in the more anthracitic or drier coals, but a more valuable product is yielded by those richer in hydrogen.
Very important distinctions-those of caking or non-caking-are founded on the behaviour of coals when subjected to the process of coking.
The caking property is best developed in coals low in oxygen with 25 to 30% of volatile matters.
As a matter of experience, it is found that caking coals lose that property when exposed to the action of the air for a lengthened period, or by heating to about 300° C., and that the dust or slack of non-caking coal may, in some instances, be converted into a coherent coke by exposing it suddenly to a very high temperature, or compressing it strongly before charging it into the oven.
Lignite or brown coal includes all varieties which are intermediate in properties between wood and coals of the older.
Cretaceous coals have long been worked in the North Island, north of Auckland, on the shores of the Bay of Islands, where the age of the coal is shown by its occurrence under the Whangarei or Waimio limestone.
In southern Otago the Oligocene beds are brown coals and lignites with oil shales, which, at Orepuki, contain 47% of oil and gas, with 8% of water.
According to one of these stories Thetis used to lay the infant Achilles every night under live coals, anointing him by day with ambrosia, in order to make him immortal.
Much important information on American coals will be found in the three volumes of Reports on the Coal Testing Plant at the St Louis Exhibition, published by the United States Geological Survey in 1906.
Lignites, as a rule, are generally found in strata of a newer geological age, but there are many instances of perfect coals being found in such strata.
The composition of the ashes of different coals is subject to considerable variation, as will be seen by Table II.
An indication of the character of the ash of a coal is afforded by its colour, white ash coals being generally freer from sulphur than those containing iron pyrites, which yield a red ash.
The amount of water present in freshly raised coals varies very considerably.
It is generally largest in lignites, which may sometimes contain 30% or even more, while in the coals of the coal measures it does not usually exceed from 5 to io%.
In cannel coals the prevailing constituents are the spores of cryptogamic plants, algae being rare or in many cases absent.
This is actually the case; the Carboniferous, Cretaceous and Jurassic systems (qq.v.) contain coal-bearing strata though in unequal degrees,- the first being known as the Coal Measures proper, while the others are of small economic value in Great Britain, though more productive in workable coals on the continent of Europe.