[14] These sub-planes are familiar to the Theosophist as gaseous, etheric, super-etheric, sub-atomic, atomic; or as Gas, Ether 4, Ether 3, Ether 2, Ether 1. [15] It must be remembered that the diagrams represent three-dimensional objects, and the atoms are not all on a plane, necessarily. [16] That is, the surrounding magnetic fields strike on each other. [17] The fifth member of this group was not sought for. [18] This, with references which appear later (pp. 32, 33, 50, etc.), relates to articles which appeared in the _Theosophist_, 1908. [19] Since writing the above I have noticed, in the _London, Edinburgh and Dublin Philosophical Magazine and Journal of Science_, conducted by Dr. John Joly and Mr. William Francis, in an article entitled "Evolution and Devolution of the Elements," the statement that it is probable that in "the nebulous state of matter there are four substances, the first two being unknown upon earth, the third being hydrogen and the fourth ... helium. It also seems probable that ... hydrogen, the two unknown elements, and helium are the four original elements from which all the other elements form. To distinguish them from the others we will term them protons." This is suggestive as regards hydrogen, but does not help us with regard to oxygen and nitrogen. [20] Theosophists call them Nature-Spirits, and often use the mediæval term Elementals. Beings concerned with the elements truly are they, even with chemical elements. [21] Quoted in "The Secret Doctrine." H.P. Blavatsky, i, 309.