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U. S. Engineers' charts to be used in connection with these

sailing directions.

STRAITS OF MACKINAC.

No. 4. Straits of Mackinac.

LAKE MICHIGAN.

No. 33. North end of Lake Michigan.
No. 50. South end of Lake Michigan.
No. 26. NE. end of Lake Michigan, etc.

No. 10. Beaver Island Group, Lake Michigan.
No. 27. North end of Green Bay, etc.

No. 35. South end of Green Bay, etc.

No. 55. Lake Michigan, Coast Chart No. 1.

No. 54. Lake Michigan, Coast Chart No. 2.
No. 52. Lake Michigan, Coast Chart No. 3.
No. 59. Lake Michigan, Coast Chart No. 4.
No. 51. Lake Michigan, Coast Chart No. 5.
No. 57. Lake Michigan, Coast Chart No. 6.
No. 58. Lake Michigan, Coast Chart No. 7.
No. 63. Lake Michigan, Coast Chart No. 8.

No. 62. Lake Michigan, Coast Chart No. 9.

The following British Admiralty charts also cover the coasts described:

No. 301. Lake Michigan.

No. 334. Mackinac Strait.

HYDROGRAPHIC OFFICE CHART.

No. 1365. Chicago, Illinois.

(IX)

CHAPTER I.

LAKE MICHIGAN.

Lake Michigan derives its name from two Indian words of the Chippewa dialect, michi (great) and sawgyegan (lake). It is the largest lake wholly within the United States and the second largest known body of fresh water in the world.

Lying in a north and south direction, it extends from long. 84° 45′ W. to long. 88° 00′ W., and from lat. 41° 37' N. to lat. 46° 05′ N., a length of 320 miles, with an average width of 65 miles. The area of this grand sheet of water is 22,400 square miles, its circumference nearly 945 miles. Its surface is 581 feet above the Atlantic Ocean, and, being 1,000 feet deep, its bottom is over 400 feet below the surface of that ocean.

The Straits of Mackinac (formerly Michilimackinac, commonly Mackinaw), from 4 to 6 miles wide and 40 miles in length, connect this lake. with Lake Huron. It is connected by canal with the Illinois River and So with the Gulf.

The shores of Lake Michigan are generally low and sandy, and the land slopes gradually to the lake. The northern shore of the lake is irregular, and more rugged and picturesque than the other shores, the summit of the highest peak being about 1,400 feet above the sea. On the eastern side are numerous sand hills formed by the wind into innumerable fantastic shapes, sometimes covered with stunted trees and scanty vegetation, but most generally bare, and rising to heights of from 150 to 250 feet. The southwestern shore is generally low, with sand hills covered with shriveled pines and burr oaks. Along the western shore, woods and prairie alternate, interspersed with a few high peaks. The cliffs on the east shore of Green Bay form a bold escarpment, and from this ridge the land slopes gradually to the lake. On this slope there is a remarkable series of drift hills and circular depressions called potash kettles.

From the appearance of the coast, Lake Michigan is believed to be moving slowly westward, uncovering the eastern and encroaching upon the western shore.

With the exception of Green and Traverse bays, Lake Michigan has few indentations in its coast line, and, excepting the north end, it is free from islands. The waters near shore are shoal, and, having few harbors, it is dangerous navigation in heavy blows. There are a number of streams flowing into the lake, but, with the exception of the Fox, flowing into Green Bay, and the Grand, Kalamazoo, and St. Joseph rivers in the east, they are unimportant.

The surface level of the lake is subject to fluctuations from one season to another as well as during the course of a season. In Lake Michigan the point of the lowest low water has been falling for seven years, and has so far fallen 5 feet. The average now is 0.16 feet below the lowest average recorded. A slight variation of the surface level is also due to a lunar tidal wave of its own. Observations have shown the difference of the level due to tide to be about 0.153 feet. At spring tides the difference between high and low water is 0.245 feet. High water occurs one-half hour after the meridian passage of the moon.

Around the lake the climate is quite equable, for, though the winter is cold and the summer hot, the waters of the lake modify the extremes. The mean temperature around the lake varies from 46° to 54°; the average rainfall is 30 to 44 inches; the mean barometer varies from 29.5 to 30.01.

The country around Lake Michigan is exceedingly rich and fertile, and an immense commerce has sprung up along this lake.

Snow falls in the north before the occurrence of the heavy frosts. The northern part of the lake only is covered with ice in winter, and it never reaches as far south as Milwaukee. Milwaukee River remains closed on an average for 100 days, from the end of November to the middle of March.

The Straits of Mackinac, which longest retain the ice, are usually open between May 1 and December 1.

The finest agricultural land in the United States is near the lake, and there is an immense trade in all grains, fruits, live stock, and lumber, and their products, as flour, pork, hides, leather goods, furniture, etc. Rich lead and copper mines abound, as also salt, iron, and coal. Abundant water power promotes manufactures of all kinds. Beer and distilled liquors are made in this region, and fine building stone is obtained from numerous quarries.

NAVIGATION.

Navigation generally opens on the lake about the middle of April and closes about the middle of December.

The two great evils to navigation are fog and snow.

There are but light currents for the master to contend with on the lakes, and, as these are the most uncertain of all elements for the navigator to calculate and allow for, the per cent of danger in lake navigation is very much reduced. Hence, the safe navigation of the lakes is dependent upon a correct compass, with a knowledge and frequent use, on the part of the master, of the azimuth tables, the precaution to take cross bearings of prominent points and from them plotting the position frequently on the chart; also the familiar use of the chart in laying courses and correcting the same for variation and deviation.

HARBORS OF REFUGE. DANGERS.

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The iron buoys are taken up every year at the close of navigation and the places marked by spar buoys of the same colors and numbers, and the lightvessels are removed about the same time. When they are replaced on the opening of navigation their positions are sometimes altered; masters of vessels are therefore cautioned to obtain the latest information on this subject and to keep their charts corrected.

HARBORS OF REFUGE.

Entrance of Sturgeon Bay Canal.-The entrance of the Sturgeon Bay and Lake Michigan Canal, on the NW. shore of the lake, has been improved by converging piers, and is now a fair harbor of refuge. Except in northerly gales the bay at the NW. end of the canal is an excellent harbor of refuge.

Milwaukee, on the western shore of the lake, has been improved. A breakwater sheltering it from NE. to SE. gales has been half completed. At present it is a very good harbor of refuge from NE. winds.

Chicago, on the southwestern end of the lake, is, with its exterior breakwater, an excellent harbor of refuge from northerly gales.

Grand Haven, with an entrance width of 390 feet, is the best harbor along the east coast for refuge from gales, but has no exterior breakwater. Little Traverse has an excellent and well-sheltered natural harbor, though it is small and some distance from the direct routes of travel.

DANGERS.

Below are the principal dangers to be encountered in the navigation of Lake Michigan, each one being accurately and minutely described in passing from Chicago to the different ports around the lake.

The eastern shore is taken first, then the western as far as and including Green Bay, then the remainder of the coast to the Straits.

SOUTH SHORE.

Between Chicago and South Chicago are:
Oakland Shoal, with a least depth of 11 feet.

Morgan Reef, with a least depth of 7 feet.

Inner Hyde Park Shoal, with a least depth of 12 feet.
Hyde Park Shoal, with a least depth of 11 feet.
Madison Park Shoal, with a least depth of 16 feet.
South Park Shoal, with a least depth of 6 feet.
Clarke Point Shoal, with a least depth of 5 feet.
Cheltenham Shoal, with a least depth of 5 feet.

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