Page:Physical Geography of the Sea and its Meteorology.djvu/467

Rh perhaps the paradox may disappear. It is held as an established fact by meteorologists that the average amount of precipitation is greater in the northern than in the southern hemisphere; but this, I imagine, applies rather to the land than the sea. On the polar side of 40° it is mostly water in the southern, mostly land in the northern hemisphere. It is only now and then, and on rare occasions, that ships carry rain-gauges to sea. We can determine by quantitive measurements the difference in amount of precipitation on the land of the two hemispheres, and it is the result of this determination, I imagine, that has given rise to the general remark that the rain-fall is greater for the northern than it is for the southern hemisphere. But we have few hyetographic measurements for quantity at sea; there the determinations are mostly numerical. Our observers report the "times" of precipitation, which, whether it be in the form of rain, hail, or snow, is called by the charts, and in this discussion, rain. Among such a large corps of observers, rain is sometimes, no doubt, omitted in the log; so that, in all probability, the charts do not show as many "times" with rain as there are "times" actually with rain at sea. This omission, however, is as likely to occur in one hemisphere as in the other. Still, we may safely assume that it rains oftener in all parts of the sea than our observations, or the rain charts that are founded on them, indicate.

826. Relative frequency of rains and gales at sea.—With the view of comparing the rains at sea between the parallels of 55° and 60°, both in the North and South Atlantic, we have taken from the charts the following figures:

That is, for every 10 gales, there are in the southern hemisphere 9 rains, and in the northern 4.7. In which hemisphere does most water fall on the average during a rain at sea? Observations do not tell, but there seems to be a philosophical reason why it should rain not only oftener, but more copiously at sea, especially in the extra-tropical regions, in the southern hemisphere than in those of the northern. On the polar side of 40° N., for example, the land is stretched out in continental masses, upon the thirsty bosom of which, when the air drops