ON ACCIDENTS. 299 



it may happen (as it often does 1 ) that a pole-chain may 

 be unhooked, or a hame strap get loose, and not be 

 discernible by lamp or moon light. But this is not all. 

 Coachmen are not philosophers, but their daily occu- 

 pation tells them that force is proportional to velocity ; 

 and, therefore, when that velocity is weakened, the pro- 

 pelling impulse is weakened also ; or, in plainer English, 

 the pressure of the coach on the wheel horses is thereby 

 diminished. With wheel horses that will hold back at 

 all, I will be bound to take a loaded coach down most of 

 the hills we now meet with on our great roads, without a 

 drag-chain, provided I am allowed to pull up my horses 

 at the top, and let them take it quietly the first hundred 

 yards. This, it may be said, would be losing time, but 

 I deny the assertion. On the contrary, time would be 

 gained by it ; for as soon as I perceived I was master of 

 my coach, I should let her go, and by letting my horses 

 loose at the bottom, I could spring them into a gallop 

 and cheat them out of half the hill (if there were one) on 

 the opposite bank. This advantage, it must be recol- 

 lected, cannot be taken, if the chain is to be put on ; and 

 I have all the time in my favour which is required to 

 put that chain on, and to take it off. 



I have before stated several objections to a locked 

 wheel, with a top-heavy load ; but I am indebted to that 

 experienced coachman, Mr. Charles Buxton, for the 

 following remark, communicated personally to me the 

 other day. ' If,' said he, ' you must lock a wheel with a 



1 I could name two most alarming accidents of this nature within the last 

 two months. 



