pomattox in 1865. He was promoted brevet brigadier-general and later brevet lieutenantcolonel of volunteers in 1865, and was promoted captain in the regular army. He was appointed first assistant in the department of engineering and chemistry at West Point in 1867, and from 1871 until his death he was professor of natural and experimental philosophy there. He served on the board of overseers of the Thayer School of Civil Engineering at Dartmouth from 1871. He was a member of a government commission to Europe in June-November 1870 studying fortifications. Author of 'Wave Motion, relating to Sound and Light' (1882); 'Life and Letters of Emery Upton' (1885); 'Analytical Mechanics) (1886); 'Hydromechanics (1887).

MICHIGAN, a State in the United States, lies in the region of the Great Lakes between lat. 41° 44′ and 47° 30′ N. and long. 82° 25′ and 90° 31′ W. It is composed of two peninsulas, a northern and a southern, between which pass the Straits of Mackinac, connecting Lakes Huron and Michigan. The State has an area of 57,480 square miles, ranking 18th in the Union. It is the largest except Georgia, east of the Mississippi. Of this area, 40,789 square miles are in the lower peninsula, and 16,691 in the upper; the upper peninsula being less than one-third the area of the State, is thus larger than any New England State, except Maine. The State's peninsular character is reflected in the legend on its seal: Si Quæris Peninsulam Amanam, Circumspice (If you seek a beautiful peninsula, look about you).

Michigan's position has closely associated its development with Ohio, Indiana and Illinois, on the south; with Wisconsin, on the west; and with Canada, on the north and east. It determined that its population should come largely from New York, New England and Canada, and from Europe. Practically surrounded by lakes and rivers, it was naturally equipped to engage extensively in lake commerce and shipbuilding. It has water communication with seven other States and with the province of Ontario in Canada, embracing together a population of about 30,000,000 people. Its chief port is Detroit, whose position, in line with natural transportation facilities to the Atlantic seaboard through the Saint Lawrence Basin and the Mohawk Valley of New York, gives it rank, in relation to immigration and commerce, with Pittsburgh and Saint Louis.

The

Climate. The position of the State in the midst of the Great Lakes gives it a climate sufficiently unique to invite comparisons. mean annual temperature has a range of about 10° - from 39° in the north to 49° in the south; July temperature, from 65° to 72°; that of January, from 19° to 25°; extreme of lowest temperatures in different parts of the State, from 49° to 15° below zero; extreme of highest temperatures, from 96° to 108°. For the year, in the State as a whole, the mean range of temperature is 50° and the extreme range 120°. The longest growing season, 170 days, is in the vicinity of Lake Erie; while the shortest growing season, 100 days, is in the west end of the upper peninsula.

The amount of rainfall varies from 29 inches in the northwest to 40 inches in the southeast; about 60 per cent of the annual rainfall is re

ceived in the crop season. The heaviest snowfall is in the region of Traverse City and in the "Copper Country" on Lake Superior. In relative humidity, Michigan is similar to the Atlantic seaboard States, but has a larger number of sunny days in summer. The annual humidity is about 75 per cent. In general, Michigan weather is extremely variable, being in the track of the largest number of low pressure areas, but the constant westerly winds and the Great Lakes tend to modify extremes.

Geology and Physiography. The oldest part of Michigan is the western half of the upper peninsula, where are found outcrops of Archean rocks granites, gneisses and schists

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as old as any on the continent of North America and similar in age to the highlands of Scotland and Norway. The highest point in the State, in the Porcupine Mountains near Lake Superior, is an outcrop of these rocks, about 1,400 feet above the level of the lake. The whole of this part of the peninsula is broken and rocky, though the drift in the valleys affords a good soil for agriculture. The region is noted chiefly for its minerals. From Keweenaw Point southwestward, across the peninsula, lie copper deposits of exceeding richness, second to none in the world. To the south and east of the copper deposits lie four rich belts of iron ore. Other economic minerals are slate, building stone, graphite, mineral paints, mica, asbestos, oil stone, gypsum, lead and manganese. East of the longitude of Marquette, the peninsula is markedly different, being a rolling, drift-covered hill country, rising scarcely 400 feet above lake level and forming the agricultural section. Along the northern shore of this portion of the peninsula, the Cambrian sandstone, formed in the ancient seas that covered the Michigan basin, has been cut by wave action into fantastic shapes, known as the "Pictured Rocks" of Lake Superior.

In the lower peninsula the arrangement of the bed rocks is simple, being like a nest of basins, one within the other. At the centre the coal basin covers about one-fifth of the area. The minerals of the other basins are various and widely distributed, among which are salt, clay, sand and gravels, limestone and gypsum. At several points are found mineral springs, where popular resorts have grown up to profit by the medicinal value of the waters; chief among these is Mount Clemens, near Detroit. The waters of four mineral springs are marketed. The surface of the lower peninsula lends itself easily to agriculture, grazing, lumbering and manufacture. In general, it is slightly undulating and but little raised above lake level. The peninsula is divided into two portions, which have a few topographical differences; the dividing line is the Grand-MapleSaginaw Valley, which, extending across it diagonally from the head of Saginaw Bay to Lake Michigan, is nowhere above 100 feet high. North of this central plain rises a plateau, between 700 and 800 feet above the lakes, forming the watershed between Lakes Michigan and Huron. At a point near Otsego Lake, this plateau reaches a height of 1,100 feet. On the north and northeast, outcrops of bed rock give the coast an abrupt and somewhat forbidding appearance. The portion of the peninsula south of the central plain rises rarely above 200 feet,

broken by low conical hills, whose fertile intervening dales form the courses of small streams. At the east, a morainal elevation, forming two watersheds, rises in Hillsdale County, 600 feet above the lakes, the highest point in this part of the State. The southeastern shore is low and comparatively level. Along a large part of the entire western shore of the peninsula, wind-blown sand dunes reach, in places, a height of 200 and 300 feet.

Off the shores of the two peninsulas lie some 200 islands within the State boundaries, the largest of which is Isle Royale, in Lake Superior. Others of the largest islands are: In Lake Superior-Grand Isle; in Lake Michigan Beaver, Fox and Manitou; and in Lake Huron Sugar Island, Encampment Island, Drummond Island, Bois Blanc and Mackinac. The coolness of the summer climate of the upper Great Lakes has made of that region a delightful watering place, particularly in the vicinity of the Straits of Mackinac. Of the island resorts the most widely known is the picturesque Mackinac Island.

Soil. The three principal soil types of the two peninsulas are determined by the relative amount of sand, clay and lime. In the southern peninsula, the soils vary from the light sandy loam of the north central plateau to heavy blue clay, on the Huron shore, and to the dark clay loam of southern Michigan. The wide distribution of sand gives warmth to the soil, and its porosity prevents the drowning of crops; while the generous depth of the soil keeps it from drying out. There is little irreclaimable marshland. In general, the soil is easy to work, presenting but little stony land like New England and very few barrens due to outcrops. The mixture of clay and sand makes a soil not too adhesive for the plow and one not easily washed full of gullies. The limestone areas are specially fortified against deterioration through wasteful farming, and in many places there is an abundance of natural fertilizers. In the upper peninsula, in the west, the rocks are either barren or thinly covered, with an occasional fertile valley; in the east, the soil is of good depth and generally rich in a variety of mineral elements.

Drainage and Water Power.-Michigan has more than 5,000 interior lakes, mainly of glacial origin. Many of those near the shores, especially of Lake Michigan, were once a part of the Great Lakes. They vary in size from an acre to a thousand acres, covering in the aggregate an area of 712,864 acres. Generally they have a border of woodland and sandy or muddy margins, with more or less vegetable and animal life. Many of these lakes are beautiful pleasure resorts. Streams are fed by these lakes, which together with them form an equable system of drainage. The rivers, though numerous, are relatively short and shallow, owing to the peninsular character of the State. Some have cut deep enough to form rapids, especially in the north, furnishing water power. Of the large power they could develop, 250,000 horse power is now furnished, mainly by the Saint Mary's, the Au Sable, the Menominee, the Saint Joseph, the Muskegon, the Grand, the Kalamazoo, the Huron and the Thunder Bay. In lumbering days, the Saginaw, the Muskegon and the Menominee were chief among

the many rivers for transportation of logs to mill. Aside from the strait-like Saint Mary's, Saint Clair and Detroit rivers, Michigan streams are not navigable, except for the smallest of river craft. Worthy of mention, besides the rivers named, are, in the lower peninsula. the Clinton, the Raisin, the Rouge, the Black and the Manistee; in the upper peninsula, the Taquamenon, the Carp, the Sturgeon, the Manistique, the Rapid, the Whitefish, Falls River and Dead River. The waters of these rivers are received by numerous bays and inlets which indent the shores; of these, the largest along the upper peninsula are Keweenaw, White Fish and the Big and Little Noquette bays; along the lower peninsula, the Grand and Little Traverse, the Thunder and Saginaw bays.

Agriculture. The chief industry of the State is farming, which engages about a third of the population. The value of farm property is double the capital in manufacturing and about one-half of the total assessed valuation of all property in the State. About one-half of the lands are in farms, of which about twothirds are improved. Of the half not in farms, about one-half would make good farm land. Less than one-fifth of the upper peninsula is in farms, with about 12 per cent of the total farming population of the State In the lower peninsula, nine-tenths of the farms and 70 per cent of the farm population is south of the latitude of the northern boundary of Midland County. In general, Michigan lands produce many kinds of crops on each farm, contributing about half of the total value. Corn is the leading crop, raised mainly in the southern part of the lower peninsula; only a few hundred acres are raised in the upper peninsula and in the northern third of the lower peninsula only about as much as in any one of the better southern counties. The wheat crop is second and has been decreasing since 1900, the yield is only Wheat about one-fifth that of Minnesota. raising tends to concentrate in the central part of the lower peninsula. Oats rank third in the