Glasgow. So far as spots are concerned, it works out to an attractive and popular resemblance to truth. Suppose a disturbance—call it hurricane or tornado—to take place in the solar atmosphere. Everything is on a gigantic scale, mountains, winds, waves in this ocean of light. A mighty updraft from below rolls back, for a longer or shorter time, the luminous solar clouds. Into the vast pit thus laid open these clouds pour a flood of light on the body and cloudy atmosphere of the sun. The former looks black against the light, but reveals mountains upwards of three hundred miles in height; the latter, with its shelving sides, returns more of the light, and is less black; while the shining matter, rolled back into waves of enormous length and height, is heaped up in fiery storms round the vast gulf. The dark body of the sun is called the macula, or spot; the better lighted atmospheric shield, the penumbra; and the heaped-up waves the faculæ, which give the sun's surface the roughness of aspect it presents.[1]
This was all that Herschel saw or imagined. It was far within the truth for awe-inspiring beauty, and for the gigantic movements of these "luminous solar clouds." Had he seen the "blood-red streak" of the total eclipse of 1706, or the "corona" and "the ruddy clouds" of that of 1715, the science of astronomy would have been perhaps half a century in advance of the position he left it in at his death. He did not see
- ↑ Had Herschel known and reflected on the letter of Sir Isaac Newton printed in his Life, ii. 455, he would probably not have published this theory. "The whole body of the sun, therefore, must be red-hot" is Newton's conclusion. Even then it would look black against the surface luminous clouds.
