SCIENTIFIC SUMMARY. 
535 
MECHANICAL SCIENCE. 
Elastic Railway Wheels. — A valuable paper on this subject was read by 
Mr. Vaughan Pendred at the Society of Engineers. After pointing out that 
repairs of way average in cost in Great Britain fifteen per cent, of -the 
working expenses of railways, being in England 220/., in Scotland 142/., 
and in Ireland 84 Z. per mile, per annum, he stated that this enormous 
destruction was due to the percussive action 
of the wheels striking the rails on an ex- 
tremely small base. To combat this wear and 
tear the tendency hitherto has been to render 
the permanent way as elastic as possible, the 
rails deflecting between the chairs, and the 
ballast giving way -under the sleepers : hence 
the necessity for stirring the ballast as often 
as it is pounded into rigidity. On the other 
hand, Mr. Pendred contends that in making 
the permanent way the elastic member of the 
system, we throw on it a function for which it 
has no fitness, and that the wheel and wheel- 
tyre should be the true yielding parts. This he would secure by making 
the tyre independent of any rigid connection with the wheel. For this 
purpose steel hoop springs, made in segments, should be introduced between 
the wheel and tyre. This system, first introduced by Mr. Adams, has proved 
eminently successful in several trials ; Staffordshire iron tyres elastically 
seated out- wearing steel tyres rigidly connected with the wheel on the ordi- 
nary plan. Now, the disintegration of rail and tyre proceeds pari passu, and 
the increased durability of the tyre is the measure of the lessened wear of 
the rail. 
Radial Axle Boxes . — Mr. Adams has also invented peculiarly-formed 
axle boxes, which allow a small amount of lateral play to the wheels of 
locomotive engines ; so that in passing round curves the line of the wheel 
base adjusts itself to that of the rails, instead of being as heretofore rigidly 
straight. An engine so fitted has been running on the North London 
Railway, passing easily and steadily round curves of 132 feet radius. 
/S 'team Coals for the Navy. — Further official trials have been made at 
Keyham of the relative evaporative power of Welsh and North Country 
coals, which afford data valuable beyond the special question at issue. They 
show the economic value, , or pounds of water evaporated per pound of fuel, 
to be for Welsh coal, taken from store, 9*34 lbs. ; Welsh coal sent as 
sample, 9*90 lbs., and with specially shortened furnaces, 10T3 lbs. ; for 
North Country coal from store, 8*26 lbs.; sent as sample, 8*41 lbs. When 
the furnace was improved by the addition of a perforated fire-door the eva- 
porative power was 9*73 lbs. with the sample of Welsh coal, and 10*44 lbs* 
with the shortened furnace ; 8*61 lbs. for North Country sample coal, and 
10*23 with the shortened furnace. For mixtures of equal parts of Welsh 
and North Country coal obtained from store, 8*79 lbs. ; of Welsh and North 
Country samples, 9*42 lbs. ; and with shortened furnaces, 9*91 and 9*54 lbs. 
respectively. With perforated fire-doors the combination of Welsh and 
Section of Elastically Sealed 
Tyre. 
