THE FEAMEWOEK OF TPIE HOESE. 



39 



length, all moving round the same common centre or 

 prop d, which corresponds to the junction of the ver- 



P 



NN' N" 



Fig. 3. 



tebr£e of the neck with those of the back in the horse. 

 Now the longer the lever the greater its power — that 

 is to say, a given weight will act more powerfully at 

 the extremity of a long lever than of a short one, in 

 the exact proportion of their relative lengths. The 

 true expression is, however, that a given weight acting 

 on a lever of this kind exercises a downward (perpen- 

 dicular) pressure in direct proportion to the distance 

 at which the perpendicular from (or through) it falls 

 from the prop. Therefore, if the head and neck, d iV, 

 be stretched out horizontally, the relative weight is 

 represented by the whole amount by which the point 

 iV lies outside the basis h h ; and if the head and 

 neck be lifted to the position d 0, it will be repre- 

 sented by the shorter distance d N' ; and if still more 

 elevated to d P, then by the still shorter one d N'\ 

 Consequently, the relative overhanging weight of those 

 portions of the horse's body may be diminished in pro- 

 portion as their position is brought nearer to that re- 



