TRANSACTIONS OF SECTION G. 503 
improper load adjustment, which are now obviated by means of swivel seatings 
so that the load is evenly distributed, 
Examples are given of roller-bearings successfully applied to the axles of 
coal- weighing shoots, each bearing supporting a load of five tons on eight rollers on 
mild-steel axles, where the total tractive resistance was reduced to 3 lbs, per ton 
of load. 
In tramway and railway vehicles a series of tests has also proved the starting 
effort to be 3 lbs. per ton of load, giving a coefficient of friction of 0:0015, including 
wheel friction upon straight level rails, This reduction effected a saving in 
electrical energy equal to 60 per cent. of journal friction, equivalent to 3d. per car 
mile, or 50/. per car per annum. 
On the Birmingham electric tramways a saving of 24°30 per cent. of tractive 
force per ton of load was obtained, and « saving of 1:055 unit per trip, equivalent 
to 384, 16s, 8d. per car per annum. 
At Southport the average energy consumption of roller-bearing cars was 
0:55 unit per car mile with a mean speed of 10:3 miles per hour, as against one 
unit per car mile with ordinary bearings and a mean speed of 8:6 miles per hour, 
The mean current consumption with ordinary bearings was 0°797 unit per car 
mile, and with roller-bearings 0°389, showing a saving of 0'408 unit per car mile, 
or a saving of 68/, per car per annum. 
As examples of railway tests, the earlier trials on the London, Brighton, and 
South Coast Railway are cited, where, after six years’ service and 120,000 miles 
run, a saving of 124 per cent. was shown in coal consumption. 
On the Indian State Railways a saving of 12°56 per cent. according to coal 
consumption, and 11:76 per cent. according to water consumption, was effected, 
or a mean of 12 per cent., equal to a saving of 135 tons of coal per train per 
annum, or 67/7. 10s. per train of six coaches. ‘Taking the life of the roller-bearing 
at ten years, and allowing for sinking fund and interest on the capital cost of the 
bearings for that period, the annual charge per train is only 0:56 per cent. of the 
actual economy effected, plus the increase of traffic obtained by longer trains 
without any appreciable increase in the expenditure of energy. 
On the Liverpool Overhead Railway roller-bearing tests proved that the 
reduction per ton mile of coal consumption was equal to 9 per cent., and that 
longer trains could be employed. 
On the Northern of France Railway the tests proved a saving in tractive 
resistance of 6 to 1 in favour of roller-bearings, at speeds varying from 50 to 
75 miles per hour. 
The reduction of tractive resistance and the correspondingly diminished wear 
and tear of materials generally, combined with increased comfort in smooth, easy 
running, the smarter handling of trains, the acceleration of speed, and the increase 
of carrying loads by means of successful roller-bearings, are subjects well worth 
the careful consideration of engineers. 
2. The Motor-Car in South Africa. By AuFrep T. HENNEssy. 
Introduction.—Aim of paper to briefly give results of practical experience in 
motor construction best suited for South Africa—As no data exist, difficulty of 
comparison of various forms of motor construction. 
Electric, Steam, and Internal Combustion Motor-Cars. 
Unsuitability of electric vehicles for South Africa—Great improvement in 
more recent construction of steam-cars—Advantages and disadvantages of the 
modern steam-car—The internal combustion motor-car best suited for South 
Africa—Consideration of detailed construction of internal combustion motor-cars,. 
The Engine—Slow and high speed—Advantage of multiple cylinders— 
Necessity of more efficient cooling—The best method of connecting up the water 
circulation. 
