Page:The New International Encyclopædia 1st ed. v. 04.djvu/151

CANADIAN LITERATURE.  edited by Lighthall, Windsor series (London, 1889); Canadian Poems and Lays, edited by Lighthall, in Canterbury Poets Series (London, 1891); Younger American Poets, edited by Sladen and Roberts (London, 1891); Later Canadian Poems, edited by Wetherell (Toronto, 1893); and Chansons populaires du Canada, edited by Gagnon (Quebec, 1865). See ; .  CANADIAN PERIOD. See .  CANADIAN POLITICAL PARTIES. See , Canada.  CANADIAN RIVER. A river formed by the union of several branches flowing east from the Taos and Culebra range of the Rocky Mountains, at the border between New Mexico and Colorado, in longitude 105° 20′ W., and about 100 miles northeast of Santa Fé (Map:, Western Part, F 3). It flows nearly due south to latitude 35° 20′ N., then east across the panhandle of Texas and into Oklahoma, where at Taloga it turns southeast, forming from about longitude 97° 55′ to longitude 96° 45′ the boundary between Oklahoma and Indian Territory. It then flows through the Indian Territory toward the northeast and joins the Arkansas River, of which it is the chief tributary, at Tamaha. It is nearly 900 miles long, but, owing to closely paralleling other rivers in the lower part of its course, it drains a relatively small territory. The volume of water varies greatly in the wet and dry seasons.  CANAIGRE, (Fr.) (Rumex hymenosepalus). A tannin-producing plant related to the docks and quite resembling the sour dock. It grows wild in the southwestern United States. The stem is nearly smooth, often reddish in color, grows from one to three feet high, and terminates in a branched flower-stalk. The leaves vary from about 2 to 16 inches in length. The roots are tuberous, somewhat resembling small sweet potatoes, and are clustered in an upright position 3 to 12 inches below the surface of the ground. The value of the plant consists in the amount of tannin contained in the roots. The tannin content in the air-dried tubers varies from about 10 to 35 per cent., a quantity exceeding that in any other tannin-producing plant. The rapid decrease in the supply of wild canaigre has caused its culture to be undertaken during recent years in the Southwest, where some extensive plantations have been established. It is propagated mainly from the roots, one ton being required to plant an acre. The land is prepared and cultivated as for other root crops. Harvesting may begin after the plant has made its full period of growth, but it has been found that the percentage of tannin increases as the roots lie dormant in the ground. In the wild state the plant makes its growth during the winter and early spring, and by early June has seeded and the tops are dead. About fifteen tons of roots per acre is an average yield. The preparation for the market consists in slicing the roots and drying them in the sun. The extract obtained is especially adapted for tanning leather for uppers, fine saddlery, etc.  CANAL (Fr., from Lat. canalis, water-pipe). An artificial channel for water, constructed
 * and

for drainage, irrigation, supplying water-power, or purposes of navigation. The design and construction of canals of large size are much the same whatever their purpose may be; in this article the general questions of design and construction for all kinds of canals will be discussed, but for specific examples of canals for other purposes than navigation the articles on, , and should be consulted.

. The two points which have mainly to be considered in canal design are the cross-section of the channel and its longitudinal profile. Considering the longitudinal profile first, it will readily be understood that a canal cannot, like a road or railway, adapt itself to the irregularities of the country by means of ascending and descending grades, but must consist of one or more practically level sections or reaches. When two or more reaches are required at different levels, the adjoining extremities of two reaches cannot be, for obvious reasons, connected by a grade in the channel. The various means for making such connections are described in the following section; but the fact which needs to be noted here is that, since the profile of the canal must consist of a series of level reaches at different elevations, care has to be exercised to select a route which will provide long reaches and consequently few changes in level. As in railway work, however, depressions in the ground may be crossed by embankments or other structures upon which the channel is carried.

Another matter which has to be carefully provided for is a supply of water to the highest reach, or summit level, as it is usually called; the reason for this being that this reach is constantly losing its water to the reaches below, and this loss must be supplied by streams or reservoirs so located as to discharge into the summit level. Distances being equal, a canal which connects two points with a single reach is preferable to one with two reaches. Indeed, a considerable increase in length is allowable to permit the canal to be constructed without a change of level. The reason for this is that transferring a boat from one level to another by locks or the other usual means is a slow operation, and furthermore, locks are very expensive to construct compared with a similar length of the ordinary channel. The engineer carefully integrates these factors of time and cost and selects the route between the various points he wishes to connect which will give the minimum time of transit at the minimum cost. In deciding upon the cross-section to be given to the channel, two things have to be considered, viz. its dimensions and its form. As regards dimensions, they are determined largely by the size of the vessels with which it is proposed to navigate the canal. The width must be at least sufficient to permit two vessels of the largest size to pass each other without fouling. Another influencing factor is that the resistance to traction is greater in a restricted waterway.

It is generally assumed that a width of bottom equal to twice the beam of the largest vessel navigating the canal regularly is necessary, and that the depth of water should be about 1½ feet greater than the draught of these vessels, if good results are to be obtained. The form of the cross-section is determined very largely by the