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before the days of photography: and he made those dark rifts practically straight lines, which misses the whole point of the structure.

When, however, we take a photograph, the eye-piece is taken away and the light shines all over the plate at once, so that we are no longer confined to a small ring, but can photograph the whole object at once, faithfully: we see that these rifts are not straight but delicately curved, in a way suggesting that there are several rings whirling round the central bright nucleus. This has a very important bearing on our ideas of the formation of stars from nebulæ: but the drawing made by Trouvelot was meaningless.

Let us take another point about a large telescope. We have chosen a telescope as our travelling car, and we must learn all about it, not only how it is used, but how it set up. You can well imagine that it is rather a business to construct a telescope like Lord Rosse's, big enough for a man to stand up in. Fig. 32 shows one in which a man is not standing up, but lying down, to do some part of the fixing. This is the great Victoria telescope which Dr. McClean presented to the Royal Observatory at the Cape of Good Hope in honour of good Queen Victoria, whom many of you may not remember. We must hope that some one will give a big telescope in honour of King George V, mustn't we?

Now not only is such a telescope awkward to set up, but it is rather awkward to work after it has been set up, unless special arrangements are made. One modern comfort is the rising and falling floor which I mentioned in connection with