Report on the Trials of Implements at Bedford. 



G85 



No. SOS?*. 



Here in No. 1308 we have a greater proportion of the total 

 weight resting upon the hind wheels, which however are of 

 smaller diameter than in No. 5038 ; therefore it may be assumed 

 that these differences would nearly balance each other. The 

 difference in the angle of inclination of the front wheels is 

 trifling, being ^ in favour of No. 5038, while those of the hind 

 wheels are equal ; 

 this difference may ^^g^. 18 and Vb.— Sections of Tyres. 



therefore be left Xo. isos. 



out of account in 

 the present compa- 

 rison. 



In No. 1308 the 

 form of the tyre is 

 convex, while in 

 No. 5038 it is flat. 



If we now look at 

 the mean draught 

 per ton of gross load 

 on the road, we 

 shall find that No. 1308 exceeds No. 5038 by 6 • 9 lbs. : but on 

 the arable land we find that their difference is only '4 Lb. The 

 reason for this must be the difference in the form of the tyre, for 

 No. 1308 has convex tyres, while No. 5038 has flat tyres, the 

 former causing the wheel to move along in a much truer line, and 

 thus preventing jarring at the edges of the wheel. On the hard road 

 we should find that flat tyres were preferable ; and they would also 

 be so on arable land, but there is great difficulty in making wheels 

 with square tyres to run in exactly true line and level ; of course 

 if they do not there will be jarring, while convex tyres, even if not 

 so exactly made, will still enable the wheel to run in a true line. 



This brings us to the next point, namely, tlie effect of sprim/s 

 in reducing draughts, and to illustrate this point, we cannot do 



■^fx'- 



