CHAPTER XXIX. 



THE METALS. 



WHAT METALS ARE CHARACTERISTICS AND GENERAL PROPERTIES OF 

 METALS CLASSIFICATION SPECIFIC GRAVITY DESCRIPTIONS. 



WE have learnt that the elements are divided into metalloids and metals, but 

 the line of demarcation is very faint. It is very difficult to define what a 

 metal is, though we can say what it is not. It is indeed impossible to give 

 any absolute definition of a metal, except as " an element which does not 

 unite with hydrogen, or with another metal to form a chemical compound." 

 This definition has been lately given by Mr. Spencer, and we may accept 

 it as the nearest affirmative definition of a metal, though obviously not 



quite accurate. 



A metal is usually supposed to be 

 solid, heavy, opaque, ductile, malleable, and 

 tenacious ; to possess good conducting powers 

 for heat and electricity, and to exhibit a 

 certain shiny appearance known as " metallic 

 lustre." These are all the conditions, but 

 they are by no means necessary, for very 

 few metals possess them all, and many 

 non-metallic elements possess several. The 

 " alkali " metals are lighter than water ; 

 mercury is a fluid. The opacity of a mass 

 is only in relation to its thickness, for 

 Faraday beat out metals into plates so thin 

 that they became transparent. All metals 

 are not malleable, nor are they ductile. 

 Tin and lead, for example, have very little ductility or tenacity, while 

 bismuth and antimony have none at all. Carbon is a much better 

 conductor of electricity than many metals in which such power is extremely 

 varied. Lustre, again, though possessed by metals, is a characteristic of 

 some non-metals. So we see that while we can easily say what is not a 

 metal, we can scarcely define an actual metal, nor depend upon unvarying 

 properties to guide us in our determination. 



Fig. 396. Laminater. 



