ON DRAUGHT. 531 



If, however, the hours of labour be lessened, taking the velocity corresponding 

 to the greatest useful effect, the results will be much greater, and the velocity 

 may be raised much higher, as will be seen in the following Table. 



Here the first column is the length of day's work, the second the best velocity 

 corresponding to that time, or half thelimit of velocity shown in Table (1), 

 and the third column the comparative effect produced, the force of traction 

 being in each case 125 Ibs. 



Duration of labour in hours. Velocity, miles per hour. Effect produced. 



2 5 578 



3 4J- 709 



4 3f 813 

 6 3 909 



6 3 1000 



7 2j 1063 



8 2 1110 



To attain higher velocity, it is necessary still further to reduce the load, and the 

 next Table is calculated upon the supposition of the strain being only one -half 

 the last, viz., 62llbs. ; this is about the average exertion of each horse in a four- 

 horse heavy stage-coach. 



Vel city ' Effect produced. 



4 51 613 



3 6f 534 



2 7| 434 



1 11 307 



In mails or light coaches, where ten, eleven, and even eleven and a half or 

 twelve miles an hour is attained, the average strain of each horse is barely 

 401bs., and the effect produced, or value of work done, not much more than one- 

 half the above. 



It must be remembered, that these tables are all calculated upon the suppo- 

 sition of the road being good, and the work such as not to cause any immediate 

 injury to the animal, and is adapted only to the average quality of horses. 

 They are not, therefore, at once applicable as data for calculations hi all ordinary 

 cases, but only serve to show the comparative forces which may be exerted under 

 different degrees of speed. The results or effects of this force will always be 

 influenced by the quality of the resistance, as we have already observed, in the 

 cases of slow travelling ; but in rapid travelling the power is much more expen- 

 sive, owing to the great loss which we see by the tables is sustained by increased 

 velocity ; and it is, therefore, the more important to study well the means of 

 applying the power in question. 



In this rapid travelling, the bad consequences of a uniform and constant 

 strain is still more felt by the horses, and the necessity of occasional relief is 

 still more urgent than at low velocities. It is universally admitted by horse 

 proprietors and postmasters, whose interests make them peculiarly sensible on 

 this point, that a flat piece of road is more destructive of horses than the same 

 length of road where gentle rises and alternate flat and swelling ground occur ; 

 and that a long hill is easier surmounted where there are occasional short levels, 

 and even descents, than when the whole is one uniform ascent. 



It only remains for us, before we dismiss the subject of the moving power, to 

 consider the particular mode of applying it, or the manner of harnessing the 

 horses. 



Under this head comes the question of the best direction of the traces, or, as 

 it has generally but less clearly been called, the angle of inclination of the line 

 of traction. This question appears to have been always considered one of great 

 importance : the point has been frequently discussed, and various opinions have 



