The Oisilly Viaduct.

(Compte rendus de la Société des Ingénieurs-civils, June, 1889, p. 953.)

This viaduct over the valley of the Vingeanne, not far from Dijon, carries a railway to Gray on the Eastern Railway of France, and was opened in October 1888. The masonry structure has a total length of 964 feet, and consists of seven elliptical arches, springing from a point 3 feet 7 inches above ground-level, and having a clear span of 121 feet 5 inches, with a rise of 47 feet 6 inches. The width of the present structure is 14 feet 9 inches, but the foundations are built to receive a double line. The width at the piers is 22 feet 6 inches including counterforts. The thickness of the arch proper is 4 feet 3 inches at the crown and 7 feet 10 inches at the point of junction with the adjoining arch. In the spandrils of the arches are three small arches of 8 feet span. The centering for each arch consisted of four principals, of which the lower part was fixed and the upper movable. Between the two parts were placed the sand-boxes, used for lowering the upper part. The settlements of the seven stone arches were found to range between and 4 millimetres. No cracks could be detected in any part of the masonry.

Calculations of strength are not given.

M. A. E.

The Canals, Roads, and Railways of Finland. By M. STRUKEL.

(Allgemeine Bauzeitung, 1889, pp. 41 et seq.)

The means of communication by road, rail and water, possessed by the Principality of Finland, form the subject of a series of articles, in which the Author deals in detail with the chief public works that have been undertaken in that country up to the present time. Finland comprises an area of 144,210 square miles, of which 15,863 square miles, or 11 per cent., are water, i.e., lakes and rivers, and 28,842 square miles, or 20 per cent., morasses and swampy ground now in course of drainage. The land is gradually rising, the alteration on the coast of the Gulf of Bothnia being at the rate of 3 feet per century, and on the Gulf of Finland about 2 feet. The population, which in 1886 numbered 2,232,378, live principally on or near the coast. Agriculture is their chief occupation, and the produce of the forests furnishes fully one-half of the total exports. The peasantry own about 54 per cent. of the cultivated land, the State has 38 per cent., and the remaining 8 per cent. belongs to the church, the nobility, and private owners. The forests cover 82,176 square miles, or 64 per cent. of the total surface of the land, and of this area 50,496 square miles, or 61 per cent. of the forests, are State property. Coal having to be im

ported, wood, which is so readily obtainable, is universally used for fuel, and was till quite recently used in Helsingfors even for gasmaking. The conformation of the land presents a series of terraces rising from south to north, with practically unlimited waterpower, so that the land is well adapted to manufacturing industries.

The water communications form the chief feature in the transport arrangements of the country, five systems or chains of lakes and rivers traversing it in a general north and south direction. These waterways are generally frozen over for some months every year, but are free from about the middle of May to the middle of November, while the coasts are free at the end of April. The harbour of Hangö on the Baltic, at the south-western corner of the coast, is seldom frozen up, except in severe winters, so that a fairly regular steamship service is maintained with certain ports of Sweden and Germany. Of the inland lines of water communication, the most easterly, or Saima system, is the most important, extending from near Kajana to Willmanstrand, a direct distance of about 220 miles. The system derives its appellation from Lake Saima, between Nyslott and Willmanstrand, from which latter town the Saima Canal communicates with the seaport of Viborg. There is a regular steam service between the towns of Idensalmi, Kuopio, Nyslott, Joensuu, and Willmanstrand, and from Joensuu northwards through the canalized Pielis-Elf to Lake Pielis. The system does not consist entirely of natural watercourses, but comprises twelve separate canals, while the Pielis-Elf navigation includes ten canals.

The Saima Canal, one of the greatest works of northern Europe, is the outcome of projects dating from two hundred years back, when the works were first begun and abandoned. The canal, as constructed, runs through the valley of the Soskuanjoki, the total length of waterway, including the string of lakes through which it passes (viz., Nujamaajärvi, Pällijärvi, Lietjärvi, Rättijärvi, Särkijärvi, Parvilainen, and Juustelaujärvi), being 36.7 miles, of which about 20 miles is the canal itself. The total fall in this length is 249 feet, for which there are fifteen locks. The ordinary width of the bed of the canal is 40 feet and depth 9 feet, with a towpath 10 feet wide; in harder soil the width of bed is reduced to 30 feet, and in hard rock to 25 feet, the towpath being 8 feet above waterlevel and 5 feet wide. The largest barges on the canal are 105 feet in length, 24 feet beam, and 8 feet 6 inches draught, the effective load capacity being 260 tons. Of the fifteen locks seven are single fall, three double, and five treble, equal together to twenty-eight falls, averaging 8.9 feet each. The locks are mostly 140 feet long; the side walls have a curved vertical section, and are 6 feet thick at the top and 8 feet at the bottom, and are also curved on the horizontal plan, the clear width of the lock at each end being 25 feet and in the centre 30 feet. On account of the disintegrating action of the frost, the lock walls are not backed up, but stand

independently of the ground behind on each side, the intermediate trench being known as the "frost ditch." In winter, also, the locks are covered over and a slight current of water maintained. On the Saima Canal the drawbridges run back on rollers by handgearing; on the Pielis-Elf swing-bridges are used. The total cost of the Saima Canal was £500,000.

With regard to the roads, although they are good in a few places, they are generally bad, and constructed on no system whatever. The landowners make and keep the roads through their own property just as they like, so that they are frequently impassable. Village roads are made about 12 feet in width, and public roads from 16 to 24 feet, widening somewhat near the larger towns.

The railways, of which there are 1,122 miles open, are all, with the exception of the short Borgå-Kervo line, State property. The chief lines, noted in the order of their construction, are:

1. Helsingfors, Tavastehus, and St. Petersburg line. The section from Helsingfors to Tavastehus was the first constructed, the line to St. Petersburg branching off at Riihimäki.

2. Hangö and Hyvinge line, from the port of Hangö, previously referred to, to a junction with the Helsingfors and Tavastehus line at Hyvinge.

3. Borga and Kervo line (private company), junction with the Helsingfors and Tavastehus line at Kervo.

4. Abo, Tavastehus and Tammerfors line, connecting the firstmentioned line with Abo, the former capital and chief port of the south-west coast, and with Tammerfors, the chief manufacturing town in the country.

5. The Wasa line, from Tammerfors to Wasa, on the Gulf of Bothnia, the chief harbour of the west coast.

6. The Uleaborg line, commencing by a junction with the Wasa line, and running along the north-east shore of the Gulf of Bothnia.

7. The Savolaks line, in the centre of the country, from Kouvola, on the Riihimäki and St. Petersburg line, to Kuopio.

The chief extensions now in hand are, in the eastern part of the country, from Viborg via Sordavala (on the Lake of Ladoga) to Joensuu, and in the central district from the termination of the Savolaks line to the Uleaborg railway. Several other lines are projected.

The construction of these lines is provided for partly by the net earnings of the existing State lines and partly by a "Communications Fund," which forms an annual item in the Budget. The land in general is easy for constructive purposes, the average gradients being 1 in 100, and the maximum 1 in 80. The rails are laid to 5-feet gauge. The bridges are numerous, on account of the watercourses, but there are few other works.

The subjoined Table shows the working results per kilometre of the above lines up to 1885, the latest date to which the Author has collated the statistics.

The Hangö and Hyvinge line has from the first incurred a deficit, but this is now diminishing, and it is hoped that the position will soon be further improved. During the first two years following the opening of the Uleaborg line, the figures were rather less satisfactory, the working of the line showing (per kilometre) :

Historical Considerations on the North Sea Canal of Amsterdam and its Capacity for Navigation by Ships of large Dimensions. By A. HUET.

(Tijdschrift van het Koninklijk Instituut van Ingenieurs, 1888-89, p. 100.)

When the North Sea Canal was opened for navigation in 1876 it was considered to afford every reasonable accommodation for the largest vessels trading to the Port of Amsterdam. But latterly the dimensions of the locks at the entrance near Ymuiden have proved to be insufficient, and now new locks are to be built to allow ships of greater tonnage to enter the canal. These facts lead naturally to the question whether it would not be advisable from an economic point of view to omit the building of these projected new locks, but to alter the locked canal into an open navigation channel, which would offer greater facilities and occasion less loss of time where a heavy traffic of large vessels is contemplated.

The history of the long series of projects for a canal to the North Sea, brought on during the last two centuries and a half, shows that the dimensions considered necessary were increased at every successive proposal, and that in the latter designs locks were omitted altogether.

The two oldest projects known for a canal through the narrow strip of land uniting the two parts of the province of Holland are by Jan Pieterszoon Dou, and date from 1629 and 1634. These were principally designed for the supply of fresh water from the Spaarne River across the Y to the polders in North Holland in summer, and for the better drainage of these lands in wet seasons, while the accommodation of shipping formed only a