_The Canals of Finland._—Finland has a considerable wealth of lake navigation, which has been connected by canals to the great gain of local commerce. One of these is the canal of the Samia, which connects a chain of lakes with the Gulf of Finland by a waterway 37 miles long, with a fall of 260 feet. The fifteen locks are all of substantial masonry, and are fitted with wooden gates, the use of iron in connection with the stonework being dispensed with as much as possible, on account of its considerable changes of volume, due to the great range of temperature to which it is exposed. The masonry, though built in hydraulic cement, suffered considerably from the severe cold of winter; but in the year 1870 the plan was adopted of covering the lock chambers by means of 2-inch planks, and allowing the water to flow perpetually through the two gate sluices. Snow is allowed to accumulate over the temporary covers, and as the water running through has a mean temperature of 39° Fahrenheit, the lock chambers are readily kept at a temperature a little above the freezing-point. The levels between the locks are kept full all winter. The practice of running out the water is stated by a recent writer to be destructive to the banks. The canal of the Pielis connects two lakes; it is 40 miles long, and has a fall of 62 feet, surmounted by ten wooden locks. The crib-work of the walls is loaded with stone, and not clay or earth, as is commonly the case, in consequence of which the woodwork is not forced out of place by the expansion of the frozen filling, and does not rot so quickly. From all that has already been put forward, it must be evident that Russia has long been fully alive to the importance of developing her maritime resources, and especially her system of inland water transport. The total canal mileage of Russia has been estimated by Sir Charles Hartley at about 200 miles(?), and he remarks that, “in most instances, they have been formed with but little difficulty across the gentle undulations of the great watershed, thus uniting the head waters of rivers which have their outlets at opposite extremities of the Continent.”[108]