4:32 Farm Mechanics. 



come the resistance the road-bed offers to the load requires 

 a steady pull of 



140 = 16011*. 



and this leaves the reserve draft to go up the grade 

 (200 X 2) 160 = 240 



The load to be carried up the grade is the weight of the 

 team plus that of the load or 



(800 X 2) + 2, 285} = 3, 885f Ibs. 



Up how steep a grade will 240 Ibs. carry 3,885? Ibs.? 

 Solving this problem by applying the principle of (531) 

 we shall have 



P. X P. D- = W. X W. D. 

 or 240 X 100 = 3, 885f X W. D. 



whence W. D. = ?? = 6.176 or 



a rise of about 6.2 feet per 100 feet, which is a 6.2 per cent. 

 grade. 



By taxing the team to its utmost capacity its effective 

 power to ascend the grade would be 



(400X2) 160 = 640 Ibs. 

 Proceeding as in the other case we shall have 



P. x P- D - = W. X W. D 



and 640 X 100 = 3, 885f X W. D. 



whence W. D. = = 16.47 



or about a 16.5 per cent, grade. That is, a grade of 16.5 

 feet in 100 feet is the steepest dirt road a team can be ex- 



