CHANGE OF CONDITIONS. 271 



and replacing it by another, is in all probability the 

 operation of a truly geological period. Many, however, 

 of the changes which are constantly going on around us, 

 are of a much more rapid character, and in these nature 

 is no slower in manipulating than the chemist. 



Had it been that the elements which are now found 

 in combination could exist in a free state, the most 

 disastrous consequences would necessarily ensue. There 

 must have been a period when many of the combinations 

 known to us were not yet created. Their elements 

 either existed in other forms, or were uncombined. 

 Our rocks are compounds of oxygen with certain pecu- 

 liar metals which unite with oxygen so rapidly that 

 incandescence is produced by their combination. Let us 

 suppose that any of these metals existed in purity, and 

 that they were suddenly brought into contact with 

 water, the atmospheric air, or any body containing 

 oxygen, the result would be a convulsion of the most 

 fearful kind; the entire mass of metal would glow with 

 intensity of heat, and the impetuosity of the action would 

 only be subdued when the whole of the metal had 

 become oxidized. Volcanic action has been referred to 

 some such cause as this, but there is not sufficient 

 evidence to support the hypothesis ; indeed, it is con- 

 trary to the opinion of most philosophers.* Such a 

 condition may possibly have existed at one time, during 

 that period when darkness was upon the face of the 

 deep, when the earth was a chaos ; but it is only adduced 

 here as an example of the violent nature of some 

 chemical changes. Potassium thrown on water bursts 

 into flame, and sodium does so under certain conditions. 

 If these, or the metals proper in a state of fine division, 

 are brought into an atmosphere of chlorine, the intensity 



* All the phenomena connected with volcanic action, and the 

 theories connected therewith, will be found in Dr. Daubeny's 

 work. A description of active and extinct Volcanoes, of Earthquakes, 

 and of Thermal Springs. 1848. 



