It will easily be seen, from the foregoing statement of physical geography, how varied must be the climatic differences of the United States. Not only is there an enormous superficial area to be taken into account, varying from 50° to 25° lat., but the whole of this area is acted upon by many natural influences, such as the proximity of two great oceans, the Atlantic and Pacific, the gigantic chains of mountains, and the still more gigantic river basins. The consequence is, that climate in the United States frequently shows the most contradictory phases. "A summer heat of the fiercest character, as at Fort Miller, San Joaquim Valley, California, is but a few miles removed from a season of even more extreme refrigeration, cold enough to require winter clothing at the midday of the summer." As an evidence of the intensity of the climatic changes, it is stated that the mean temperature of New York is the same as that of Liverpool, yet the difference between the mean temperature of the three summer months and that of the three winter months is twice as great in New York as in Liverpool. Throughout England the heat of summer is insufficient to ripen Indian corn, while the ivy that grows luxuriantly in England can scarcely survive the severe winters of New York.

COAL BASINS.

LIKE every other country which has obtained any degree of industrial supremacy, America depends principally upon her coal measures, which, even taking into account the enormous extent of territory covered by the American flag, are a matter of wonder both to the geologist and industrial observer. Nature was in one of her most bountiful moods when she stored up such vast reservoirs of fuel for the future States, for there is no country on this earth which possesses coal-fields of such extraordinary thickness and extent. Though comparatively young in years, America already stands second of the coal-producing countries of the world, Great Britain being the first. Before going into the details of the American coal-fields, it will be well to give a general outline of their extent as far as known; for it must be borne in mind that the progress of coal discovery has been rapidly developing, as the more recent States in the west have become settled. In 1845, for instance, the area of coal measures was stated to be 145,000 square miles, whereas in 1866 it was known to exceed 200,000; and in 1873 it was estimated at 291,485, with the strong probability of the existence of as many more in the west. The amount of coal contained beneath this surface may be fairly considered illimitable, for the Pennsylvanian coal-beds alone, which occupy only 12,472 square miles out of the number, are estimated to contain a supply which, at the present consumption of 20 or 25 million tons per annum, would last for 640 years, even if 50 per cent. were allowed for waste.

K

The coal-beds of the United States may thu summarized, taking them from east to west :

1. The New England field, which occupies an of 500 square miles in the States of Vermont, Ma chusetts, and Rhode Island. The coal-beds, w consist of anthracite, or stone coal, underlie the c of Providence and Newport, but they have b worked in a desultory manner and are not very portant commercially.

2. The Pennsylvanian anthracite field is of lim extent, only 470 square miles, but of enormous ductiveness and value. There are also very la bituminous beds in Pennsylvania to which allus will be made further on; and though the anthra coals of the United States bear no proportion in extent of the measures to the bituminous coals, t possess features of remarkable interest, no country the world being able to show such a development anthracite, or so much energy in working it. Th coals lie almost entirely within the State of Penns vania; commencing a little to the north-west Philadelphia, and occupying in the main two oblo districts about 40 and 60 miles long respective The production for 1877 was as follows:-Wyomi district, 8,300,000 tons; Lehigh district, 4,400,00 Schuylkill district, 8,600,000; Loyalsock distri 23,000, the total yield of the year being 21,323,00 The whole workable amount of the Pennsylvania field is estimated at 13,180,288,000 tons, one-thi of which is in the area owned by the Philadelphia ar Reading Iron and Coal Company, one of the large of the American corporations. The coal strata ha

been geologically much disturbed, the result of which is that the beds lie near the surface (requiring no very deep coal-pits) and that they are of extreme thickness -one of them, indeed, called the Mammoth Vein, varying from 40 to 100 feet. In the north-eastern portion of the State, the whole district underneath the Lackawanna Valley is completely honey-combed with anthracite workings, the towns of Carbondale and Scranton, with a population of about 50,000, being built on them; and the coal is carried away by a most ingenious railway, called the "gravity line," which runs over the mountains for 16 miles to the shipping places by a series of inclined planes worked by twentyeight stationary engines.

3. The Alleghany field is an enormous one, occupying 53,895 square miles in the States of Pennsylvania, Ohio, Virginia, West Virginia, Kentucky, Tennessee, Alabama and Maryland. All these coals are bituminous, or free-burning. Extending as this basin does through so many States, it is necessary to specify the individual areas a little more closely. (a) The Pennsylvanian coals are principally worked in the counties of Tioga and Clearfield in that State, the annual product of the first-named district being about 600,000 tons. (b) The Ohio field occupies 10,000 square miles in that State, coal being worked in upwards of thirty counties. The chief development lies in the south-eastern portion of the State, in the counties of Hocking and Athens, where it has given rise to a considerable iron trade. (c) The Virginian field is extensive, though not worked to the amount of which it is capable. It is apparently an

extension of the Ohio beds, the West Virginian coals, principally gas-coals, occupying an area of 16,000 square miles. The chief mines are found in the valleys of the Kanawha, and New River, and in the neighbourhood of the Ohio and Baltimore railways. There are also large beds of coal in Virginia, on the western side of the Shenandoah Mountains, and in the districts between the James and Potomac Rivers. (d) The Tennessee field is of very great extent, but is comparatively little worked. Its chief mining

centres are on the Coal Creek River in Anderson County, not far from Chattanooga. (e) The Maryland field is largely worked at Cumberland, the annual yield being nearly 2 million tons. (f) The Kentucky field occupies the south-western portion of that State to the north of the Cumberland plateau, and is continuous with the beds of the Tennessee field. Kentucky is fortunate in sharing, in its eastern portion, some of the beds of the central field. (g) The Alabama field is also continuous with the Tennessee coal measures, a good deal of coal being mined in the valley of the Tennessee River, near Decatur, and sent by rail to the iron district of Nashville.

4. The Central coal-basin is of great importance, embracing 40,000 square miles in the States of Indiana, Illinois, Kentucky, Iowa, Missouri and Arkansas. (a) The Illinois field occupies the lion's share of the Central basin, the beds running across the state from Wilmington, near Chicago, in a southwesterly direction to Springfield and the Mississippi valley. There are more than 350 mines in this State, yielding annually 2 million tons.

(b) The