406 REPORT— 1901. 



roughly said to consist of a castor frame in which the single wheel is 

 held, the wheel being capable of being loaded to any required amount. 

 The castor frame is attached to the tractor, the pull on the wheel or 

 tractive force being taken through a bell crank frame on to a small ram, 

 so that by fluid pressure the tractive force can be continuously recorded. 

 The following are Mr. Mallock's general suggestions : — - 



1 . Variable radius of wheel, load, and speed. Begin with five wooden 

 wheels, with iron tyres 2 inches wide ; diameter of wheels, 5 feet, 4 feet, 

 3 feet, 2 feet, 1 foot. These to be tried each with increasing loads, beginning, 

 say, at 500 lb., and at two, four, six, eight, and ten miles per hour. 



In the first few sets of experiments small increments would be made 

 of the lo.ids, as it is probable that for each kind and state of road thera 

 may be one or more critical pressures. Experience will show how large 

 the increments may be without loss of accuracy in the resistance-in- 

 terms-of-load curve. If suitable apparatus is used it might be expected 

 that a complete series of experiments, both for variations of radius and 

 load, could be completed in a day. 



2. The experiments should be repeated with the roads in various 

 conditions of wetness. After the variations of resistance in terms of 

 radius and load have been well worked out, one or two diameters might 

 be selected with which to try variations in the width of the tyre. The 

 widths should range from 1 inch to 10 inches. 



3. Trials might then be made of various classes of tyres, such as solid 

 rubber, pneumatic tyres, &c. 



4. Some method should be devised to classify and describe the con- 

 dition of the roads. 



5. Every series of experiments should begin and end with a trial of 

 some particular wheel for the sake of reference. 



Sir David Salomons : — 



All vehicles to be loaded to 1 ton, 1^ or 2 tons, as the case may be, to 

 avoid calculations. 



Gradients to be taken by percentages, say 2, 2^, 5, 7h, 10, 12^, and 

 15 per cent. 



Nature of surface classified, such as asphalte dry, wet, and greasy ; 

 wood dry, wet, and greasy ; macadam dry, wet, muddy, freshly laid, 

 worn, very worn. 



Experiments to be made on roads laid with syenite, granite, Maidstone 

 stone, Sevenoaks gi'avel, flint. 



Also when rough laid before rolling and after rolling. 



Also cinder, sand, beach, and other roads. 



Traction measured when from standstill at two, five, ten, twelve, 

 fifteen, eighteen, twenty, twenty-five, and thirty miles per hour. 



Wind and air resistance to be calculated from actual registering 

 apparatus to give net results and air resistance. 



Air experiments might further be made thus : — 



Flat front of vehicle and same at back built of light board. 

 Front conical to cut air and back flat. 



Front and back both conical. 



Wheels might be steel, solid rubber, pneumatic tyres, flat, and rounded. 



Various diameters of wheels, those generally adopted, and a few trials 



