360 



Lincoln Tractor Trials, 1920. [July, 



for the items of attendants and fuel only, calculated on the 

 net ploughing time and the total fuel used. 



Average figures for five tractors in each class which 

 performed the work in the shortest time and with the lowest 

 fuel consumption are perhaps of more assistance than any 

 other comparative figures for judging class against class; but 

 comparison is vitiated by the warning that in any class the 

 five speediest may not be the five most economical in fuel. 

 Again, certain tractors were permitted to compete in both 

 Classes I and II, and there is no indication as to whether 

 or not the same tractor appears in the first five in both classes. 







Average of Five Lowest. 



Class. 



Land, 



Time in hours 



Fuel in gal. 



Wages in pence 



Fuel cost in 







per acre. 



per acre. 



per acre. 



pence per acre. 



I 



Light 



1-92 



2-90 



34-5 



66 7 





Heavy 



1-96 



3-84 



35-3 



88-4 



II 



Light 



1-21 



2-96 



21-8 



68-0 





Heavy 



1-52 



3-63 



27-4 



CO 



VII 



Light 



1-89 



2-84 



33 9 



6.5-3 





Heavy 



2-08 



3-78 



37-4 



86-9 



The judges suggest that to compare the figures for fuel con- 

 sumption it is convenient to adopt " equivalent acres," i.e., 

 " the number of acres that would have been ploughed if the 

 drawbar pull had remained constant at 500 pounds per plough- 

 share, estimated from the actual drawbar pull observed and 

 the actual area ploughed." The resultant figures cannot, how- 

 ever, be anything but arbitrary, and it seems better on the 

 whole to adopt the actual recorded figures. 



Accepting the figures at their face value it will be deduced 

 that in the case of the more efficient tractors in each class 

 there is very little to choose in the matter of fuel consumption, 

 and that while the tractors pulling three-furrow ploughs had 

 the advantage in time there is practically nothing between 

 Class I (tractors pulKng two furrows) and Class VII (motor 

 ploughs). While these factors are of great importance, they 

 are far from covering the whole range of questions which 

 should determine the choice of a tractor, as for example: — 

 Consumption of lubricating oil, dilution of lubricating oil by 

 condensation of fuel, time taken to dismantle wheel grips, 

 time taken to equip tractors for road-haulage, quite apart from 

 a most important factor which short-period trials cannot be 

 expected to discover, namely, cost of maintenance. Various 



