farther north, and Edmonton became the fur market. Edmonton is today the ambitious capital of the newly-formed province of Alberta, but it still remains the greatest raw-fur depot in the world. When, however, it ceases to be the end of the rail, and when the present plans for building a road into the new North materialize, the fur trade center will be shifted to the banks of the Peace river, where a new town will grow up to dominate the region beyond.

For the rail is going north, into the mighty top-country of the continent. With farmers already settling on its prairies and the government conducting experiments in agriculture and horticulture, with two fully organized and well equipped corporations now boring for oil and gas, with the coal-hunger constantly increasing, and with the old-time fur trade still as important as ever it was, the need and practicability of a railroad into the last north is one of today's industrial facts.

Another important engineering enterprise is the improvement of the Lesser Slave river, which connects Lesser Slave lake and the Athabasca river, and which would be an admirable waterway but for twenty-two miles of rapids. These are to be overcome by the building of a series of wing dams, for which the Canadian government has made a grant as its first move in the way of public works in the North. When these have been built, during the present year, there will be a continuous waterway of four hundred miles into the Peace river country. A next step will probably be the cutting of twenty miles of canals, which would connect 3,000 miles of navigable waters radiating from Fort Smith, on the Mackenzie: an easy bit of work that would give an internal water system almost unrivaled in the world.

With trains and with more steamers, the silent places will be silent no more. The white man, as he goes north, carries his noise with him.

This passage is to be effected by means of a steel and concrete tunnel, similar in general design to others now in operation, but in the construction of which perplexing engineering problems are to be solved by entirely novel methods.

For many years, both freight and lim

its trestles the tonnage of the road and fitted to eliminate those obstacles which have placed the certain direction of trains practically beyond mortal control. With the development of such traffic conditions, however, as would justify such an undertaking, the commerce of the great

tral is east bound, west bound freight cars being largely empties, so that the tunnel grade from the center of the river to the portal on the Canadian side is one and one-half per cent. That on the Michigan side is one-half of one per cent. greater, the easier grade thus being provided for the heavier business.

of material made, that one might well imagine that thoroughly disciplined, well seasoned campaigners were in the field, throwing up immense fortifications, as defenses against a formidable enemy. On either side of the river, blacksmith shops, sawmills, warehouses for the storage of supplies, machine shops and substantial

office structures have
been erected. The ap-
proaches are marked by
broad, deep timber-lined.
cuts, on whose
whose high
banks temporary rail-
road tracks, for the han-
dling of materials, pick
their way between tow-
ering piles of heavy
logs waiting to be cut
into desired lengths be-
fore they are lowered
away into the "hole" at
one of the six shafts, for
use as supports in the
excavation work.

At every point of attack, the tendency to eliminate human muscle is apparent, steam being substituted wherever possible. Like grim spectres of power, sturdy derricks extend the long gaunt arms of their cranes as if in benediction over the workmen beneath them and vapory clouds of exhaust come puffing from the lungs of small high power engines that pant and strain under the load of their separate burdens. At frequent intervals elaborate and expensive mechanisms for the handling of materials have been installed. Millions of yards of concrete are used in the construction of retaining walls and arches, but of the gravel and cement used in its preparation, not a shovelful is moved by hand. From the moment the gravel is picked up from the river or lake bottoms, by means of the big "sand-suckers" which pump greedily

Apparently a determined army of invasion has taken its position along the line of the tunnel survey, great scars in the earth marking the irregular rushes of its deploying skirmish line. So systematically are the men directed and tests

yard after yard through canvas tubes let. down from the deck of a barge, to the time it is mixed with the cement, every handling, done with cranes and bucket shovels, means a few feet more elevation. Finally the gravel rests in spacious bins, built at the top of high trestles or platforms. By a similar process the cement is placed in an adjacent elevated bin. Both this and the gravel are allowed to run, by means of chutes, into a huge mixer just below the bins. The properly proportioned mixture of gravel, cement and water-the resultant concrete-is then dumped into small cars which run on a still lower trestle, to be carried to the point at which it is to be finally applied.

used. In this way the disagreeable features of smoke and consequent bad air in the tunnel will be eliminated.

Of the various plans originally suggested, for the method of construction, one included the use of a dredged trench in the river bed, partially filled with concrete and containing twin tubes of reinforced concrete, eighteen feet in diameter. This proposition involved the placing of saddles in the concrete footing in the trench, the sinking of forms on them, the filling in of concrete about the forms and their final withdrawal, followed by the building of an inside reinforced

The details of this great engineering work have required a little more than two years for their final adjustment and yard after yard of blue prints has marked the successive stages in the working out of the approved specifications, until the engineers' diagrams have roughly divided the tunnel work under the following heads: Westerly open cut, 1,540.07 feet; westerly approach, 2,128.97 feet; sub-aqueous, 2,625 feet; easterly approach, 3,193.14 feet, and easterly open cut, 3,300 cut, 3,300 feet, making the total distance of excavation a little more than 2.42 miles from surface to surface. The approach tunnels are twin concrete structures, between which a bench or retaining wall of the same material is four feet in lateral thickness. In chambers along this wall will be placed conduits, through which power, telephone and telegraph cables will be strung. The side walls will vary, as earth formation and pressure necessitate, from two feet and nine inches, to five feet in thickness.

When the tunnel is completed, which it is now thought will be about June 1, 1909, all cars will be operated at the terminals by means of high power electric locomotives, a third rail system being

lining. Another plan was the excavating of a tunnel by means of the usual shield method, the idea being to first deposit on the river bottom a blanket of clay, under which the operation of tunneling might be carried on.

The final plans, however, included a modification of the first proposal, and it was decided that the object of the work could best be attained by building steel tubes on shore, excavating in the river bed a trench, in which a steel cradle for the reception of the tubes should be imbedded in a footing of concrete, the sinking of the tube shells within the arms of the cradle and the final depositing around them of a complete covering of concrete. The cradle feature and the elimination of the use of a cofferdam, comprise a method never before attempted in subaqueous tunnel construction.