26 WELLS'S NATURAL PHILOSOPHY. 



TILITT, PLIABILITY; FLEXIBILITY, TENACITY, HaBDNESS, 



and Bkittleness. 



These are not, as is often taught, distinct, independent properties of matter, 

 like magnitude, porosity, inertia, etc., but modifications of the force of attraction. 



What is Mai- 45 MALLEABILITY is that property in virtue 

 leabiiity? ^£ whicli a suLstance can be reduced to the 

 form of thin leaves, or plates, by hammering, or by means 

 of the intense pressure of rollers. 



' In malleable bodies, the atoms seem to cohere equally in whatever relative 

 situations they liapper. to be, and therefore readily yield to force, and change 

 their positions without fracture, almost like the atoms of a fluid. 



The ^rope^ty of malleability is possessed in the most eminent 



What are ex- degree by the metals ; gold, silver, iron, and copper being the 



Malleability? most malleable. Gold may be hammered to such a degree of 



thinness, as to require 360,000 leaves to equal an inch ia 



thickness. 



What is Due- 46, Ductility is that property in virtue 

 tihty? ^£ ^jjjgj^ ^ substance admits of being drawn 

 into wire. 



"We might suppose that ductility and malleability would belong to the same 

 substances, and to the same degree, but they do not. Tin and lead are 

 highly malleable, and are capable of being reduced to extremely thin leaves, 

 but they are not ductile, since they can not be drawn into fine wire. Some 

 substances are both ductile and malleable in the highest degree. Gold has 

 been drawn into wire so fine, that an ounce of it would extend fifty miles. 



-^ , 47. Flexibility and Pliability are those 



What are 



fnd'^piiabu properties which permit considerable motion 

 "y? of the particles of a body on each other, with- 



out breaking. 



What is Te- 48. TENACITY is that property in virtue of 

 nacity? -vvhicli a body resists separation of its parts, by 

 extension in the direction of its length. 

 ■wTiatis 49. Hardness is a property in virtue of 



Hardness? which the particlcs of a body resist impression, 

 separation, or the action of any force which tends to change 

 their form, or arrangement. 



When is a 50. A body, whose particles can be removed, 



bodyboft? ^^^ changed in position, by a slight degree of 

 force, is said to be soft. Softness is, therefore, the oppo- 

 site of hardness. 



