two and a half times that on the Earth! Boneless, watery, pulpy inhabitants of the cold waters; or they may be frozen so far as to exclude the idea of animal existence; or it may be restricted to shallow parts in a planet of ice.[84] But if this be so, to what end his gorgeous array of satellites?—his four moons? “Precisely the same,” answers our pertinacious Essayist, “as the use of our moon during the countless ages before man was placed on the earth; while it was tenanted by corals, madrepores, shell-fish, belemnites, the cartilaginous fishes of the old red sandstone, or the Saurian monsters of the lias. With these _differences_, it is asked, what becomes of analogy—of resemblances justifying our belief that Jupiter is inhabited like ourselves?” To this answers Sir David Brewster—Jupiter’s great size “is alone a proof that it must have been made for some _grand_ and _useful_ purpose:” it is flattened at its poles; revolves on its axis in nearly ten hours; has different climates and seasons; and is abundantly illuminated, in the short absence of the sun, by its four moons, giving him, in fact, “perpetual moonlight.” Why does the sun give it days, nights, and years? Why do its moons irradiate its continents and seas? Its equatorial breezes blow perpetually over its plains? To what purpose could such a gigantic world have been framed, unless to supply the wants, and minister to the happiness, of living beings? Still, it is admitted,[85] “that certain objections or difficulties naturally present themselves.” The distance of Jupiter from the sun precludes the possibility of sufficient light and heat from that quarter, to support either such vegetable or animal life as exists on the earth; the cold must be very intense—its rivers and seas must be tracks and fields of ice.[86] But it may be answered, that the temperature of a planet depends on other causes—the condition of its atmosphere, and the internal heat of its mass—as is the case with our earth; and such “may” be the case in Jupiter; and, “if” so, may secure a temperature sufficiently genial to sustain such animal and vegetable life as ours; yet, it is owned, it cannot “increase the feeble light which Jupiter derives from the sun; but an enlargement of the pupil of the eye, and increased sensibility of the retina, would make the sun’s light as brilliant to Jovians as to us.”[87] Besides, a brilliant phosphorescent light “may” be excited in the satellites by the sun’s rays. Again, the day of ten hours may be thought insufficient for physical repose; but, it is answered, five hours’ repose are sufficient for five of labour. “A difficulty of a more serious kind,[88] however, is presented by the great force of gravity on so gigantic a planet as Jupiter;” but Sir David gives us curious calculations to show that a Jovian’s weight would be only double that of a man on the earth. Struck by such a formidable array of differences, when he was in quest of _resemblances_ only,