CO A I. 



111.' 



COAL 



Built on tli*' Chile" was formerly as high 

 praise for a vessel as is now the familiar "Al 

 t \ I.|, rring to the great London ship- 



ping insurance company. The river is formed 

 l>y a t ouiliin ition of many small mountain 

 streams draining the counties of Lanark, Ren- 

 frew and Dumbarton, and flows through some 

 ii the most romantic scenery in Scotland. The 

 most important point on its banks is Glasgow, 

 und Mow this city it gradually expands into 

 the great estuary known as the Firth of Clyde. 

 The actual river is only seventy-five miles 

 long; the broad estuary is ninety miles in 

 length. In 1812 the first European steamboat 



was launched on the Clyde and since that date 

 its waters have received the hulls of thousands 

 of the finest vessels afloat. 



CLYTEMNESTRA, kly i> m )<<*' tra, in Greek 

 mythology, the unfaithful and treacherous wife 

 of Agamemnon and half-sister of Helen, Castor 

 and Pollux. The poet Homer tells how, during 

 the absence of her husband in the war against 

 Troy, she bestowed her favors on Aegisthus. 

 On Agamemnon's return they murdered him to 

 hide their guilt, and together governed My- 

 cenae for years. Her son Orestes later avenged 

 his father's death by killing both Clytemnestra 

 and her lover. See AGAMEMNON; TROY. 



OAL. In 1902 in Pennsylvania, the 

 most important field of anthracite coal in the 

 world, there was a strike of miners. It lasted 

 >< long that in some localities factories were 

 obliged to close; in many parts of the country 

 people could not obtain fuel for warming their 

 houses, and before the strike was settled the 

 industrial system of the country was sadly 

 disarranged. This strike illustrated in a very 

 forcible manner the dependence of all indus- 

 tru> ujxm this universal fuel. 



What Coal Is. If we burn wood in a closed 

 vessel so that only a little air can get to it 

 we obtain a black substance which is nearly 

 all carbon. We call this substance charcoal. 

 What we may do on a small scale in making 

 charcoal . Nature in the past ages did on a large 

 Mle in making the coal which we now take 

 from the mines. 



Possibly you have stood beside a marsh and 

 noticed that in spots it was filled with a kind 

 of mow. that seemed to be dead underneath 

 und alive on top. Cutting down into this moss 

 usually shows it to have a thickness of several 

 feet, and to be more compact near the bottom 

 than at the top. In Ireland and other regions, 

 America included, this moss occurs in large 

 quantities, and in Europe it is dried and used 

 for fuel under the name of peat. Now if this 

 peat had been buried deeply in the earth and 

 subjected to intense heat, it would have been 



turned to coal, something like the charcoal. 

 We may say, then, that peat is coal in the 

 process of formation. 



Ages before man lived upon the earth por- 

 tions of it were covered with a dense growth of 

 vegetation far more luxuriant than that found 

 now in the densest tropical jungles. By the 

 lowering of the level of the land these vast 

 forests were covered by the ocean, and while 

 resting for ages on the bottom of the sea they 

 were buried in mud. The land again rose and 

 appeared above the ocean. The mud was 

 hardened into rock and the buried vegetation 

 by heat and pressure was turned into coal. 

 This process was repeated many times through 

 the uncounted ages and for this reason we 

 find the coal in veins, one above another and 

 separated from each other by layers of rock. 

 Green plants grow only under direct sunlight. 

 Since the plants of the Coal Period owed their 

 growth to the influence of the sun, coal is 

 sometimes called buried sunshine, a very appro- 

 priate name. 



Mineral coal, as hard and soft coal are gen- 

 erally called, differs from charcoal in several 

 particulars. Since it was formed under great 

 pressure it is more compact, and since the 

 air was practically excluded during its forma- 

 tion many of the gases that are driven off in 

 making charcoal were changed into substances 

 that combined with the coal. These are com- 



