 Each acre of a coal seam, four feet in thickness, and yielding one yard net of pure fuel, is equivalent to about 5,000 tons ; and possesses, therefore, a reserve of mechanical strength in its fuel equal to the life labour of more than 1,600 men.  The Mining Magazine: Devoted to Mines, Mining Operations, Metallurgy, &c., &c - Σελίδα 491857Πλήρης προβολή - Σχετικά με αυτό το βιβλίο
 | 1860 - 566 σελίδες
...very small portion, as we shall presently see, of the vast coal fields which stretch across the globe. Each acre of a coal seam, four feet in thickness, and yielding one yard net of pure coal, is equivalent to about 5000 tons, and possesses, therefore, a reserve of mechanical strength... | |
 | Manchester district Sunday school assoc - 744 σελίδες
...far in advance of him in his favourite art. To Tie continued.) THE PHYSICAL POWERS OF ENGLAND. — Each acre of a coal seam four feet in thickness, and yielding one yard nett of pure fuel, is equivalent to about 5,000 tons ; and possesses, therefore, a reserve of mechanical... | |
 | 1857 - 648 σελίδες
...unscientific minds. Professor Rogers, of the United States, furnishes us with the following estimates : — Each acre of a coal seam, four feet in thickness, and yielding one yard nett of pure fuel, is equivalent to about 5,000 tons ; and possesses, therefore, a reserve of mechanical... | |
 | Perry Fairfax Nursey - 1857 - 642 σελίδες
...unscientific minds. Professor Rogers, of the United States, furnishes us with the following estimates : — Each acre of a coal seam, four feet in thickness, and yielding one yard nett of pure fuel, is equivalent to about 5,000 tons ; and possesses, therefore, a reserve of mechanical... | |
 | 1858 - 314 σελίδες
...this subject Professor Rogers furnishes the following estimates : — " Each acre of a coal-seam 4 feet in thickness, and yielding one yard net of pure fuel, is equivalent to about 5000 tons. Each square mile of one such single coal bed contains eight million tons of fuel, equivalent... | |
 | United States. General Land Office - 1860 - 226 σελίδες
...that an acre of coal, three feet thick, is equal to the product of 1,940 acres of forest trees, and "each acre of a coal seam, four feet in thickness, and yielding one yard of pure coal, is equivalent to 5,000 tons, and possesses, therefore, a reserve of mechanical strength... | |
 | John Henry Pepper - 1861 - 516 σελίδες
...our respect for coal as the equivalent or exchange for human labour increases. Thus we are told "tnat each acre of a coal seam, four feet in thickness, and yielding one yard net of pure coal, is equivalent to about five thousand tons, and possesses, therefore, a reserve of mechanical... | |
 | James Ansley Hingeston - 1863 - 442 σελίδες
...unscientific minds. Professor Rogers, of the United States, f urnishes us with the following estimates : — " Each acre of a coal seam, four feet in thickness,...reserve of mechanical strength in its fuel equal to the life labour of more than 1,600 men. Each square mile of one such single coal bed contains 3,000,000... | |
 | 1864 - 364 σελίδες
...this subject Professor Rogers makes the following calculations : — " Each acre of a coal seam, 4 feet in thickness, and yielding one yard net " of pure fuel, is equivalent to about 5000 tons. Each square mile of one " such single coal bed contains eight million tons of fuel, equivalent... | |
 | Robert John Walker - 1864 - 406 σελίδες
...'that an acre of coal, three feet thick, is equal to the product of 1,940 acres of forest trees ; and each acre of a coal seam four feet in thickness, and yielding one yard of pure coal, is equivalent to 5,000 tons, and possesses, therefore, a reserve of mechanical strength... | |
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