OF ATTITUDE. 105 



OF THE ATTITUDES. 



72. The term attitude is applied to any position of the body 

 that is permanent during any considerable time. 



[In order to explain the mechanism of the attitudes it will be 

 necessary to enter into some of the details which properly belong 

 to the study of physics. 



73. All bodies when left to themselves, tend towards each 

 other, from the influence of a general force called aft ruction, and 

 the force with which one body attracts another, is great in pro- 

 portion as its mass id larger comparatively than that of the at- 

 tracted body. 



74. Now, the mass of the earth being incomparably larger 

 than that of the animals, plants, stones, and all other objects 

 spread upon its surface, attracts them unceasingly, and tends to 

 cause them to fall towards the centre of the globe. 



75. In order that a body shall rest in the position it occupies, 

 it must be sustained by something capable of resisting this force 

 of attraction, and which does not give way under its weight, 

 such as the solid surface of the earth itself, or an inflexible body 

 placed between it and this surface. 



76. We name, base of support, the space occupied by the 

 points by which an object supports itself upon a resistant body, 

 or the space comprised between these points. 



77. In order that a solid body shall rest motionless or immova 

 ble, upon its base of support and not fall, it is not necessary that 

 all its parts should be thus sustained ; it is enough to sustain it by 

 a single point, provided this point be placed in such a manner that 

 if a part of the mass fall towards the earth, another part op- 

 posite to it and of equal weight, be elevated as much ; the weight 

 of one part counterbalancing the other. Centre <>f gravity is the 

 name given to the point about which all points of a body recipro- 

 cally balance each other, and if it be sustained, it is sufficient to 

 maintain the entire mass in place. 



78. It follows then that to prevent a body from falling, it is 

 sufficient that its base be placed vertically beneath its centre ol 

 gravity. 



11. What is meant by attitude? 



73. What is attraction? 



74. Why do all bodies tend t-> fall towards the centre of the globe ? 



75. What condition is necessary that a body may preserve its position 1 



76. What is meant by base of support? 



77. What is meant hy centre of gravity? 



78. What is necessary to prevent a body from falling ? 



