The appearance of this 'tumultuous cloud, instinct with fire and nitre,' is always amazing. Sir Robert Ball considers it one of the three most remarkable objects visible in the northern heavens, the other two being Saturn and the Great Cluster in Hercules. But, beautiful and wonderful as both of these may be, the Orion Nebula conveys to the mind a sense of mystery which the others, in spite of their extraordinary features, never suggest. Absolutely staggering is the thought of the stupendous dimensions of the nebula. Professor Pickering considers its parallax to be so small as to indicate a distance of not less than 1,000 years light journey from our earth! It is almost impossible to realize the meaning of such a statement. When we look at this shining mist, we are seeing it, not as it is now, but as it was more than a hundred years before the Norman Conquest; were it blotted out of existence now, it would still shine to us and our descendants for another ten centuries in virtue of the rays of light which are already speeding across the vast gulf that separates our world from its curdled clouds of fire-mist, and the astronomers of A.D. 2906 might still be speculating on the nature and destiny of a thing which for ages had been non-existent! That an object should be visible at all at such a distance demands dimensions which are really incomprehensible; but the Orion Nebula is not only visible, it is conspicuous! [Illustration: PLATE XXX. Photograph of the Orion Nebula (W. H. Pickering).]