What is the fourth sphere of Heaven?

You must know that there must be order in the great unfoldment of human from our earthly condition to the higher life in which abound all the material chemical productions of earth until we reach the fourth sphere. 

From there, you will perceive a change, which will again change the chemical, but not the being. 

Here a new light is given, a new voice, which proclaims a new birth—a new spiritual birth—where all the dross of material conditions is removed at the threshold to again step forth to an unseen world—and on being ushered to this sphere, the most wonderful and glorious effulgence of light breaks upon the newborn spirit and reveals to it what the senses could never have conceived. 

Here you behold a host who are gathered to chant forth angelic music. 

From this sphere you will commence your angelic ascensions to the fifth, sixth and seventh until you reach the great ocean of eternal beauty where sphere after sphere unfolds among the planetary nebula of the spiritual kingdom—where are concentrated hosts of glorious spirits at work, carrying out the fulfillment of life in every sphere and planet.