because the Sun also helps to cause tides, but you see the effect is small, and we will not notice it further.

Fig. 72.

But now suppose the series of marks is, owing to some cause or other, broken up. For instance, suppose that, instead of stopping at one place, you travel about to different places. Then the diagram would be altered as in Fig. 72, which I call the "American Tourist's Bathing Timetable," because