Water tanks below deck serve to trim the boat and furnish a supply for the boiler.  The dredger cuts by swinging on a center spud 16 in. in diameter, and moves forward from 8 to 10 ft. at each fleet.

The Roberts Island dredger, of which the Ajax is an improved copy, handles steadily 700 yards per day of 12 hours, in the stiffest and most tenacious clay in which it has been worked; and ranges from that average to 1,500 yards per day in soft, peaty mud.

The Ajax was built by Farrington, Hyatt & Co., of the Stockton Iron Works.

This type of dredger can be built for about $12,500, and we are informed can be relied on for a monthly average of 26,000 yards in any material met with in the overflowed lands near Stockton, delivered 50 ft. ashore, at a height of 10 or 12 ft. above the ground line.—­Min. and Sci.  Press.

* * * * *

THE FLEXIBLE GIRDER TRAMWAY.

This is an ingenious proposition for utilizing a modification of the wire tramway system for overcoming obstacles (while retaining the ordinary wire tramway or any light railway on other parts of the line), made by Mr. Charles Ball, of London.

The flexible girder tramway is an improved system of constructing a modification of the well known and extensively used rope or wire tramway, and it is claimed that it will revolutionize the transport of the products of industrial operations from the place of production to the works or manufactory, railway station, shipping ports, or place of consumption; and that in the result the introduction of the flexible girder tramway will in many cases enable profits to be earned in businesses which have hitherto been unremunerative.  It is declared to be at once simple, cheap, durable, and efficient.  The improvement consists in the employment, in addition to the usual tram wire (a hempen rope, a wire rope, or a metallic or other rod), along which the load is transported, of a second or suspension wire or rope to which the tram wire is connected by tension rods or their equivalent at intervals between the rigid supports or piers, the object being to diminish or distribute the sagging or deflection of the tram wire, and thus lessen the steepness of the gradients over which the load has to be transported.  The combined tram wire, tension rods, suspension wire, and accessories are, for convenience, designated a “flexible girder.”

Another improvement consists in using, when a double line is employed, stretchers or crossheads to keep the flexible girders nearly parallel to each other, so that when necessary the load to be transported may be suspended from or borne by both tram wires jointly or simultaneously, thus permitting a load of greater weight than that for which each single tram wire is intended to be carried over the system.  One indisputable claim for confidence in the flexible girder principle