Vital Physics. 57 



special properties of brittleness and tenacity in a higher 

 degree than iron possesses when uncombined. 



The mode in which caloric is suddenly or slowly 

 abstracted from the steel is the chief cause of the 

 particles of iron being equally or unequally adjusted each 

 to each, and therefore of the metal being elastic, or brittle 

 and hard ; as well as that it contracts unequally without 

 air or gas, as it cools down. 



Gold will illustrate the matter in another form ; it is a 

 soft, but remarkably ductile or malleable metal. How can 

 this be explained ? 



Supposing the ultimate atoms of gold are superficially 

 held together each to each by an external attractive fluid, and 

 repel each other centrally, but that these two fluids are not 

 equal in proportion each to each, but that the external 

 attractive fluid or force is considerably plus that of the 

 central repellent force, it follows that adhesion to each 

 other's surfaces will be sustained to the level of their intact 

 integrity, however finely beaten out ; because the attractive 

 force being plus on the surface, the edges of the atoms 

 will adhere to each other, whilst the repellent being minus 

 very considerably, under ordinary circumstances, the force 

 applied from centre to centre of each atom will be unequal 

 to destroy the plus of the superficial attractive binding 

 force, and so fine continuous extension is sustained. Again, 

 from the repellent force being small in each atom, 

 it is slow to receive caloric in each particle, till that 

 fluid is present in a concentrated form, as great heat, 

 when it melts the gold. Hence the high degree at which 

 gold melts, or its particles acquire central repellent 

 force sufficient to overcome superficial attraction, and 

 separate particle from particle. Yet, for strength, the 

 attractive force not being central, toughness and hardness 

 are not attained. 



