convertibility of our protectors. The chief safety from this danger consists in our getting our vessel into the tide of a "downrush," passing through one of the "spot" openings, and thus being wafted, swiftly and almost free alike of danger and of energy-cost, into the sub-photospheric solar atmosphere, where every cause of alarm is at once ended.
All this was what White had admirably planned. Presently we found ourselves sailing, rapidly but quietly, through what, although comparatively a small "spot," was none the less a vast expanding gulf of some ten thousand miles across. The "spotty" seasons are thus the readiest for solar ingress; but the bold and experienced navigator can always find and make good his entrance somewhere over the ever-disturbed equatorial and sub-equatorial region,—the lesser openings, in fact, of a mile or even less breadth, being often safer than the greater, owing to their comparative freedom from the dreaded dangers of the storm-raised faculæ.
And now, passing through penumbral walls or precipices, we enter within the mighty sun. As soon as we had sunk beneath the level of the dazzling photosphere, our eyes could open upon the genial scene that expanded in all its vastness before and beneath us. The light clear hydrogen atmosphere stretched for many thousands of miles below, resting its lower strata upon the diversified surface of the sun's solid body. White had to slacken speed, of course, when he approached the corona and the hydrogen atmosphere outside, and now, as we descended, and had still more to slacken speed with the
