At sufficiently high temperature, then, all matter must be in an incandescent gaseous state, and _vice versa_ at a low temperature it is a solid mass. With these short notes we have also outlined the history of our own earth. The same gaseous state in which our sun is at present belonged once to the earth according to science of today. During enormous periods of time the incandescent matter of the earth radiated light and heat into the cold universe. Finally so much heat was lost that chemical attraction could assert itself. Regarded as a sun, the earth was then dying and it entered upon the chemical era. During this state the elements combined with each other according to general chemical laws into such compounds as were the necessary outcome of their atomic weights, valence, and positive or negative qualities. In this connection it is sufficient to point out that these processes must go on incessantly until compounds have been formed in which the chemical forces have reached equilibrium and rest. In the case of our planet these products formed the solid crust of the earth, the primeval rock, the mineral world, further water and finally air, the oxygen and nitrogen of which may be considered as remains of the elements. Furthermore, according to a law known to science as that “of the least resistance,” chemical reactions proceed from compounds which have more energy to such as have less, wherefore it follows that each product was as poor in energy as the conditions at the time permitted. If we now especially give our attention to the combustion taking place in chemical processes, this era may also be called the period of combustion or the general world-fire, names which are exact even if we use combustion in the common, limited sense of oxidation. Oxygen is considered to constitute about one-half of the solid crust of the earth, and when to this quantitative preponderance is added its extraordinarily strong affinity to other elements, these must with necessity burn into oxides just as has been the case. It is therefore with the products of combustion, that is to say, the ashes and the remains from a general colossal world-fire, that the earth enters its planetary state, at which stage it becomes suitable for the creation and evolution of living beings. It is from burnt substances that the organisms must form the combustible matter that constitutes their material clothing. How can this be done? In the only possible way; that is, by again decomposing the products of combustion into their elements and bringing them into such combinations that a new combustion may take place. Are the products of combustion able to perform this transformation spontaneously? They have just lost the fund of energy that could have made them combustible and this lost heat must again be stored up and therefore taken from some other source, as no heat can be created from nothing.