If a mass of ice formed in the manner described is placed in a vessel, and being just covered with a film of oil, to prevent the absorption of air, is melted over a lamp or fire, and the heat continued, it will, so far from being converted into steam at 212°, continue to increase in temperature up to 270° or more, and then burst into ebullition with such explosive violence as to rend the vessel in which it is confined. From this experiment we learn that did water exist in any other condition than that in which we find it--even with the apparently simple difference of containing no air--it would not be safe to employ it in any culinary or manufacturing operation, since its use would be followed by explosions as dangerous as those of gunpowder. Such researches as these prove to us the admirable adaptation of all things to their especial ends--the beautiful adjustment of the balance of forces throughout creation. The refinements of Grecian philosophy saw, without the aids of inductive science, that the outward vesture of nature covered a host of mysterious agencies to which its characteristics were directly due. In their dream of the four elements, fire, the external and visible form of heat, was regarded as the cause of vitality, and the disposer of every organised and unorganised condition of matter. Their idealisations have assumed another form, but the researches of modern science have only established their universality and truth. The great agents at work in nature--the mighty spirits bound to never-ending tasks, which they pursue with unremitting toil, are of so refined a character, that they will probably remain for ever unknown to us. The arch-evocator, with the wand of induction, calls; but the only answer to his evocation is the manifestation of power in startling effects. Science pursues her inquiries with zeal and care: she tries and tortures nature to compel her to reveal her secrets. Bounds are, however, set to the powers of mortal search: we may not yet have reached the limits within which we are free to exercise our mental strength; but, those limits reached, we shall find an infinite region beyond us, into which even conjecture wanders eyeless and aimless, as the blind Cyclops groping in his melancholy cave.[83]