[ 286 ] 



XLII. Results of some Experime?its on the actual Force of 

 Draught of Carriages upon common Roads. By B. Bevan, 

 Esq. 



To the Editors of the Philosophical Magazine a?id Annals. 

 Gentlemen, 

 ''I "'HE aci\\a\ force qf draught of carriages upon common roads 

 -*■ has become a subject of interest and importance, as it re- 

 lates to the principles of conveyance by rail-roads, and more 

 so as it demonstrates the importance of attention to tlie sur- 

 face of the road. I therefore take the liberty of sending 

 you the results of some experiments of mine on that subject, 

 conducted with considerable care in August 1824. 



These experiments were all made, or reduced to roads per- 

 fectly level or horizontal, to separate the mechanical force due 

 to the inclination of the hill or plane from the force necessary 

 to overcome the friction of the carriage in its ordinary state 

 as affected by the condition of the road ; and by way of ren- 

 dering them comparable with other experiments which have 

 been or may yet be made on this subject, I have considered 

 the gross load of the waggon and burden to be divided into 

 1 000 parts. 



Description 

 of Road. 



Force 

 of Draught. 



240 



165 



163 



Loose sandy road •^166 

 I 190 

 I 240 

 I 215 

 L240 



Mean 204 ...orith. 



C 1"! 

 Turnpike road new 



gravelled 



Mean 



Ordinary bye-road 



Mean 



.or -fth. 



106 nearlyl-9^ 



Desci-ipiion Force 



of Road. of Draught, 



(-61 



Hard compact loam < 36 



161 



Mean 



Dry hard turf .... 



Mean 



Turnpike road with 



a little dirt 



more dirt 



Mean 



53 nearly-rs" 



th. 



i 40 

 40. ..or -sVth. 



I 30 



39 



34j..,or^th. 



C "^O 

 Turnpike road free S „Jj 



from dirt Y^ 



Mean 



31 

 304 



From which it appears that^t;^ horses will draw with equal 

 ease the same load upon a good hard turnpike road, as thirty- 

 three horses can do upon loose sandl Or, if we assume the 

 value of draught, upon a well-formed road in good condition, 

 at sixpence per ton per mile, the equivalent price of draught 



will 



