omers cannot believe in the possibility of the "finger"; but in any case it seems clear that something on the Sun causes the storm, because the storm is repeated when the Sun has turned round once. But you will no doubt notice that the marks are by no means always exactly one below another, though they may be nearly so; sometimes there is
Fig. 73.
a slope in one direction and sometimes in another, which means that the cause is recurring either a little more or a little less rapidly than the time for the Sun to go round. The real fact is that there is no one special time which we can assign as that in which the Sun rotates, because he is not solid. When you stand on one of these nice new escalators at the tube stations, all the platform moves together because it is made of solids; but a liquid stream
