The nature of shipping and its development have been closely dependent upon the depth of the channels connecting the different lakes, particularly the passages between Lake Superior and Lake Huron, and between the latter and Lake Erie. Prior to 1858 the channel entering Lake Saint Clair was only 9½ feet in depth, but by means of appropriations of the United States Government one of the entering channels was deepened to 13 feet by 1871, and to 16 feet by 1874, in which state it remained until 1887, when the work of deepening began anew and it was completed to a depth of 20 feet. The Detroit River was not originally so shallow, and with the improvements given it during the period from 1874 to 1890 a channel 20 feet deep was secured for a breadth of 440 feet. The Canadian Government is now constructing a canal from Lake Saint Clair to Lake Erie which will greatly shorten the route. The construction of the first canal at Saint Mary's Falls was begun under a land grant of the State of Michigan by a private corporation in 1853, and was opened with a depth of 12 feet in 1855. Under an appropriation of the United States Government the canal was deepened between 1870 and 1881 to a depth of 16 feet, and has since been excavated to a depth of 20 feet. Canada has also constructed a canal around these falls, but it is much less used than the United States Canal. The Wetland Canal, connecting Lake Erie and Lake Ontario, has been completed by the Canadian Government to a depth which admits the passage of vessels with a draught of 14 feet. The United States canals are free. With each successive deepening of the channels the size and draught of the vessels constructed have been increased with a resulting cheapening of the rates, which in turn has tended to increase the traffic and stimulate the tributary industries. A number of vessels now in use have a draught of 17 feet. Some of them have a length of 500 feet and carry 8000 tons of cargo.
Besides their great length these vessels differ from the ocean type in that they are flat-bottomed, the purpose being to carry the greatest possible cargo on the shallow draught to which they are limited. On no other waters is so great a cargo carried on so small a draught. Many of the larger vessels besides carrying their own cargo take one or more barges or sailing vessels in tow. Many of the vessels classed as sailing vessels are little more than barges, their sails being spread only when the wind is especially favorable. Prior to 1883 the tonnage of the sailing vessels exceeded that of the steam vessels, but since that date the tonnage of sailing vessels has remained about constant while that of steam vessels has almost trebled. In 1897 the gross tonnage of steam vessels was 975,000 tons, the sail vessels a little over one-third that amount, and the barges 55,000 tons. The total gross tonnage of the lakes increased from about 450,000 tons in 1870 to 600,000 tons in 1886 and 1,370,000 tons in 1897. The accessibility to resources of coal and iron has given the lake region unequaled advantage in the construction of ships. In 1897 the 120 vessels built on the Great Lakes had a greater tonnage than the 137 vessels built in other parts of the United States. Treaty provisions prevent the United States from building war vessels on these waters. The increase in lake traffic has been much greater than the increase in tonnage. This is due to the greater rapidity both of sailing and of loading and unloading vessels. The efficiency in the latter respect is not equaled in any other part of the world. A round trip from the head of Lake Superior to the eastern Lake Erie ports is now made in ten days. Thus an average of twenty round trips in a season can easily be made. Freight rates have fluctuated greatly from year to year so that the comparison of years may be misleading, but the general downward tendency has been very rapid. At the end of the nineteenth century coal was carried from Buffalo to Duluth at the rate of one-half mill per ton mile, which was only a small fractional part of the expense by rail. Wheat was carried the same distance at a per mile rate that was cheaper than that current in ocean traffic. The fact that coal constitutes a large product for return shipment makes a much lower rate possible than could otherwise be secured. The movement of freight upon the lakes is characterized by the great predominance of the east-going traffic over the west-going trade (especially the east-going traffic from the Lake Superior region), and by the importance of the Lake Erie ports for the exchange of the east-going for the west-going products, and by the fact that the bulk of the traffic centres upon a very few commodities.
Formerly the lower lake region was of greater relative importance, but in consequence of the enormous increase in iron mining in the Superior region, and also the increase in lumbering and grain raising in the tributary region during the last decade of the nineteenth century, the increase in the tonnage of lake shipments during that period was mainly in the tonnage originating in the Lake Superior region. The concentration of the transfer of the east-going for the west-going traffic on the Erie coast is due principally to the fact that it is through these ports the iron ore must pass to reach the coal and the smelting region, while in turn, in consequence of the nearness of these ports to the coal mines, they are the most convenient points for the loading of the coal, which constitutes the bulk of the west-going freight. Lumber also finds the shortest route to the manufacturing centres through these ports, and grain here makes connection with the Erie Canal, whence there is an easy transit to the Atlantic coast. It is probable that the latter product would be carried on the Saint Lawrence route much more extensively than it is if the canal around the Niagara Falls were to be deepened so as to admit the passage of the large lake vessels. According to the Government reports for 1900 the total net tonnage of freight upon the lakes was 36,033,200 tons, distributed as follows: Receipts of mining products, 23,541,203 tons; receipts of agricultural products, 5,220,285 tons; receipts of forest products, 3,523,188 tons; receipts of manufactured products, 277,393 tons; receipts of miscellaneous products, 3,471,131 tons. The commerce through the Detroit River on the part of vessels registered at American ports increased from 21,684,000 tons in 1890 to 30,000,000 in 1899.
The registered tonnage passing through the Saint Mary's Falls Canal in 1860 was 403,657 tons; in 1890 8,454,435 tons, and in 1900 23,315,834 tons. The net tonnage passing through the canals in 1900 was 25,643,073. Of this 20,532,493 tons was eastbound—19,102,494 tons going through the United States Canal. The number of
