Firmament

Firmament, a word formerly used to signify the vault of heaven. The term found its way into English from the Vulgate, which renders the Septuagint stereōma, and the Hebrew rakia, by the Latin firmamentum (Gen. i. 6). Rakia (from the verb raka, 'to beat or strike out') signifies whatever is expanded or stretched out, and was specially employed by the Hebrews to denote the hemisphere above the earth, compared (Exod. xxiv. 10) to a splendid and pellucid sapphire. Elsewhere (Ezek. i. 22-26) it is spoken of figuratively as that on which the throne of the Most High is placed. Hence it follows that the notions of solidity and expansion were both contained in the Hebrew conception of the firmament. The blue ethereal sky was regarded as a solid crystal sphere, to which the stars were fixed (compare the cælo affixa sidera of Pliny, ii. 39 and xviii. 57), and which was constantly revolving, carrying them with it. This sphere or firmament divided 'the waters which were under the firmament from the waters which were above the firmament;' and the theory of the phenomena of rain, &c. was that there were 'windows in heaven'—i.e. in the firmament, through which, when opened, the waters that were above the firmament descended. 'The same day were all the fountains of the great deep broken up, and the windows of heaven were opened' (Gen. vii. 11). The view entertained by the Greeks and other early nations was essentially the same. In the progress of astronomical observations it was found that many of the heavenly bodies had independent motions, inconsistent with the notion of their being fixed to one sphere or firmament. Then the number of crystalline spheres was indefinitely increased, each body that was clearly independent of the rest having one assigned to it, till a complex system was introduced, capable of being fully understood only by the philosophers who formed it (see PTOLEMAIC SYSTEM). It was long before men conceived the idea of the possibility of a body being maintained in motion in space without a fixed support, and, considering the number of phenomena of which the hypothesis of a crystalline firmament offered an apparent explanation, we must regard it as having been in its day a curious and ingenious speculation.