WEIGHT. 33 



body, therefore, will be attracted most strongly, that is, will weigh the most, 

 at the polea, or at that portion of the earth's surface which is nearest the 

 center, and weigh the least" at the equator, or at that portion of the earth'a 

 surface which is most remote from the center. 



A ball of iron weighing one tliousand pounds in the latitude of the city of 

 New York, at the level of the sea, will gain three pounds in weight, if re- 

 moved to the north pole, and lose about four pounds if conveyed to the 

 equator. 



Bw does 62. If a body be lifted above the surface of 



as we'^aslend the cartb, its weight will decrease in accord- 

 ed th'8''''6ur- ance with the law, that the attraction of 

 face? gravitation decreases upward from the surface, 



as the square of the distance from the center of the earth 

 increases. 



The weight of a body, therefore, will bo four times greater at the earth'a 

 surface, than at double the distance of the surface from the center ; or a body 

 weighing one pound at the earth's surface, will have only one fourth of that 

 weight, if removed as far from the surface of the earth, as the surface is from 

 the center. 



How does ^"^- As the attraction of gravitation decreases 



weight vary dowuward from the suitace to the center of the 



as we descend 



fr^°i thesur- earth, simply as the distance decreases, weight 

 will decrease in like manner. 



A body weighing a pound at the surface of the earth, will weigh only half 

 a pound at one half tho distance from the surface to the center. 



Where will ^^' ^^ *^® ceutcr of thc earth a body will 



body have no neccssarilv lose all wei<2:ht, since, being sur- 



weight? •' , & 5 5 ?3 



rounded on all sides by an equal quantity of 

 matter, it will be attracted equally in all directions, and, 

 therefore, can not exert a pressure greater in one direction 

 than in another. 



What are -^^ ^^^® attractive force which the earth exerts upon a body 



heavy and is proportioned to its mass, or to the quantitv of matter con- 

 li'^ht bodies ? ■ . . ^ j 



tained in it, and as weight is merely the measure of such at- 

 traction, it follows that a body of a large mass will be attracted strongly, and 

 possess great weight, while, on the contrary, a body made up of a small 

 quantity of matter, will be attracted in a less degree, and possess less weight. 

 "We recognize tliis difference of attraction by calling the one body heavy and 

 the other light. 



If, as is represented in Fig. 4, we place a mass of lead, a, at one extremity 

 of a well-balanced beam, and a feather, 6, at the other, we shall find that the 



2* 



