50 THE BEGINNINGS OF LIFE. 



phosphorus 1 , as well as arsenic., antimony and other 

 metals, also exist in allotropic states in which they 

 exhibit wholly different properties. It will be easily 

 understood, therefore, that in compound substances a 

 greater and greater possibility of molecular rearrange- 

 ment arises in proportion to their atomic complexity. 

 Gradually, in fact, this becomes the all -important 

 character of a compound, and one to which the nature 

 of the constituent atoms is altogether subordinate. In 

 proof of this, one has only to refer to the multitudes 

 of isomers with wholly different properties which are 

 compounded of carbon, hydrogen, and oxygen, in the 

 same relative proportions. 



Although so much depends, therefore, upon the 

 number and arrangement of the atoms in the molecule, 

 still the properties of the molecule can be nothing 

 more than the resultant of the properties of the dif- 

 ferent atoms modified by their mutual influence upon 



trimetric system, and also in rhombic prisms belonging to the mono- 

 clinic system. The latter have a deep yellow colour and are translucent : 

 they always exhibit a great tendency to pass by molecular rearrange- 

 ment accompanied by an evolution of heat into the opaque, straw- 

 yellow, octahedral crystals. 



1 The two varieties of this substance are known by the name of 

 Normal and Red Phosphorus. The first variety is much more poisonous 

 than the second; it is also colourless, crystallizable in rhomboid do- 

 decahedra, soluble in sulphide of carbon, easily oxidizable, phospho- 

 rescent, and inflammable at a low temperature. The second form is 

 scarlet red, amorphous, much less soluble, non-phosphorescent, and only 

 inflammable at high temperatures. Mr. Lemoine has shown that heat is 

 the most available means for converting the one form into the other, 

 and that the transformation is always only partial. 



