POWERFUL one hundred and forty ton floating crane has been built in Germany for use in hauling the boilers and heavy machinery into the Mauritania, the new turbine express Cunard passenger steamer, under construction at Wallsend-on-Tyne, England.

In the past, the shear-leg construction has been favored in floating cranes. With this system the feet of the forelegs lie at the pontoon gunwale and the load is passed between the legs. There are certain disadvantages in this: the loads to be handled have to be limited

by the sloping position of the fore shearlegs; the outreach of the crane from the turning point of the hook cannot be used to its full extent, as even at a small inclination the legs will come in touch with the side of high ships; and the legs become clumsy and expensive, owing to their great length.

In the crane under consideration the turning points of the jib are kept back from the pontoon gunwale, and sufficient space is left in front of them for taking up the loads, which need no longer be passed between the crane legs. By further withdrawing the turning point of the foot of the jib another advantage is

secured in that the legs do not come in contact with the vessel's side. The crane can lie close along the side of the ship, and the jib, as far as the screw spindles will permit, may be adjusted towards the outside with comparative ease.

From a constructional point of view the new shear-leg crane has another advantage, as the whole jib can be built of lattice work and a comparatively light weight obtained, and, in addition, the principal parts of the jib can, if desired, take an angular shape, and need not be led in a straight line.

The machine is of huge dimensions. The smallest radii are nine feet and sixteen feet respectively. The lifting gear for the large hook carries eighty tons at the greatest out-reach, eighty feet, and 140 tons at fifty-nine feet radius. At a breadth of pontoon of seventy-seven feet a free space of about twenty-five feet width remains on the deck in front of the jib to admit of the shipping of articles. The crane is driven by a twin screw engine, the diameter of the cylinder being eleven inches and the stroke one foot six inches. The motion of the engine shaft is conveyed to the main shaft by means of a pair of spur wheels. Three change gears on the three lifting gears are arranged on this main shaft. The first change gear, counted from the bow of the ship, drives the large lifting gear for 140 tons; the second one is used for driving the screw spindles for adjusting the jib, and the third one is employed for putting the small lifting gear for twenty tons into operation. Both of the lifting gears are equipped with change wheels in order to obtain two different speeds. The working speeds are as follows: large hook, lifting of loads to seventy tons' weight, six feet per minute; test load, 175 tons. Small hook, lifting of loads to ten tons' weight, fifty feet per minute; from ten to twenty tons, twenty-five feet per minute. The large hook carries the loads in ten falls of rope, the small hook in four. The lifting ropes have a safety factor against breaking, of eight to ten.

Each lifting gear permits of both ends of the rope being wound up simultaneously, for which purpose the lifting gears

are equipped with two separate rope drums. The hooks are arranged on ball bearings, and are easily movable. The lifting gears are fitted with a brake of approved type. The mechanism for adjusting the jib consists of spur and bevel wheel gears, and two screw spindles of Siemens-Martin steel. All the turning. parts are fitted with lubricating arrangements, and, where necessary, are protected. The controlling of the driving engine and the change gears, as well as the working of the brakes, is done from the attendant's stand on the fore part of the jib.

Besides the lifting gears for twenty and one hundred and forty ton loads, a further independent lifting mechanism of special construction is located on the deck of the barge between the sides of the protecting frame.

This lifting gear, driven by a special reversible twin steam engine, actuates a small crab of five tons' lifting capacity. The track of this crab is arranged underneath the jib from the knee to the top of the crane nose, and has, therefore, a length of about fifty-six feet. The idea in this is to effect the shipping of small loads from the deck of the pontoon, or from a shute, lying between the pontoon and ship, without having to adjust the heavy jib. A special device of the respective lifting gear admits of the moving of the load on the hook always parallel to the present position of the lower flange of the jib. This small handy lifting mechanism is controlled from the elevated platform, previously alluded to, as is the case with the other lifting gears.

The pontoon carrying the crane has a length of ninety feet, a breadth of seventy-seven feet, and a depth of about fourteen feet. It is divided into nine compartments, which are serving partly as ballast tanks, and partly as dwelling and engine rooms. The pontoon is steered by two rudders, actuated by the aid of a winch with hand gear.

IX-WHEELED trucks for motor cars and motor omnibuses are the greatest innovation of the present season in motoring. Previously fashion has dictated the use of four wheels for vehicles of this class and, as the majority of men are slaves to custom, it is not surprising that, as the automobile succeeded the horse-drawn vehicles, its maker should adopt the fourwheel style of build. It has been accepted practice in railroad engineering to use six drive wheels on heavy locomotives, the line of reasoning followed being "more driving wheels more friction and less wear," but only during the closing days of last year did this principle find an able exponent in its application to vehicles propelled by hydrocarbon or other types of motors.

The six-wheeled system, as illustrated herewith, is the outcome of the joint ef

forts of two French engineers, MM. Janvier and Robin, both closely identified with the engineering department of the French army, which body has already seen fit to utilize these machines in the transporting of officers within the zone of hostilities as well as to entrust to them the transportation of military stores over long distances. In the Janvier-Robin system the front pair of wheels, assisted by the rear pair, is used for supporting the ends of the frame and also for steering the machine, whereas the middle pair constitutes the driving members, they being connected by chains and gears with the motor of the vehicle. Paramount in this system as well as in other six-wheeled systems is the mounting of the vehicle body on the three axles so that all six wheels are constantly in contact with the road surface. This calls for a flexible suspension of the center axle so that at times when the forward

axle passes over an obstacle, or encounters a depression in the road surface, the center axle with its wheels is not in the first case lifted clear off the ground, and in the second instance compelled to carry the major part of the vehicle weight; at which times it would become a fulcrum for the entire machine.

In overcoming this difficulty, recourse has been had to a peculiar system of springs for supporting the framework on the axles in which four springs are required for each side of the vehicle. Supported on the front axle is a conventional semi-elliptical spring shackled direct at its forward end to the vehicle frame. Mounted on the rear axle is a similar spring shackled at its rear end to the frame. The rear end of the front spring in turn links to an intermediate spring which at its center is attached to the vehicle frame, but at its rear end has connection with the central axle. In rear of the central axle is another spring which forms a connecting link between this axle and the forward end of the spring carried on the back axle. Thus there are on each side of the vehicle four

springs, forming a continuous compensating linkage from the front to the back axle and permitting of the center axle's being raised or lowered, thereby accommodating itself to the variations in road surface. Nothing better illustrates the success attained in this line than the fact evidenced by tests in which the vehicle was driven over a series of obstructions from two to twelve inches in height. At not a single moment while passing over the series were the center wheels out of contact with the road while the front or rear wheels were mounting the obstructions.

Having solved the problem of using three axles with their three sets of driving wheels, the next problem was deciding on the exact advantages gained by their use. In tests determining these the first and most prominent was that of increased road friction due to a fiftypercent increase of the tractive surface between the wheels and the road. This appealed particularly to the military engineers, as the military service requires constant operation in rough places and in all kinds of weather, two conditions

demanding a maximum of road adhesion. Another favorable consideration is that of smoother running than four-wheeled machines. To explain: Should the front. wheels drop into a road depression the downward movement of the front of the body is obstructed by the central axle and its two compensating springs, and should the front wheels encounter a large log, or stone, the quick upward throw of the body is similarly restrained by these compensating springs. There is through the medium of the central axle and its springs a state of equilibrium maintained between the front and rear axle which is entirely wanting in fourwheeled machines. Added to these two merits is a third-the absence of skidding. or slipping when turning a corner at high speeds. Skidding is the great problem in four-wheeled motor cars, due largely to the greater load carried on the back axle in comparison with the front axle. To avoid this cars have been made longer and the back axle placed well to the rear instead of directly beneath the back seat, but while a slight amelioration has resulted it has not been a cure.

The

six-wheeled machine uses the front two and back two wheels for steering and in turning a corner to the right the front two wheels are turned to the right and the back pair to the left, while the center pair propels the car. This arrangement swings the car around in a smallerdiameter circle than where the front wheels only are turned, in which case the back wheels in their effort to follow the tracks of the front pair skid over the road surface, endangering the vehicle and other vehicles and also wearing out the pneumatic tires, which are so considerable an item in the running of a car. great has been the anti-skidding achievement that under test it was impossible to make the car skid turning a corner at a legal speed and the steering by front and back wheels allowed of turning a car in less space than needed for a four-wheeled machine. In commercial vehicles the custom is to make the center pair of wheels of large diameter and fit them with exceedingly wide rubber tires, these tires taking the form of rubber pads mounted angularly on the wheel rim and giving excellent service on all roads.

So

A

LTHOUGH thousands of telegraph operators have been forced out of the profession through paralysis of their hands and fingers in the manipulation of the Morse key, it is only within. the past two years that improvements in this crude instrument have begun to be made.

Dynamos have been substituted in place of the old chemical batteries in the making of the telegraphic currents, and with the coming of the dynamos a greater study of mechanics on the part of telegraphers who were ambitious to become chiefs of staff.

With this study of mechanics came a realization of the waste of energy in the manipulation of the old-fashioned Morse

lever key. It was found that two motions of the hand were required to make the single dot or the single dash and that the Morse letters, having an average of four dot and dash characters, required an average of eight movements of the hand and arm in their formation.

A rapid sender-a sender who could average as good as thirty words per minute-it was found, was required to move his arm up and down at the rate of 1,200 to 1,500 times per minute. Many men were compelled to continue this rapid spring-like movement for many hours at a stretch, and when the figures were considered, electricians marvelled that the arms of fine operators held out as long as they did. Many of the first-class men have been known to maintain a speed of fifty words a minute for several con