Robert H. Scott

“ At any place where an area of relatively high pressure comes into close proximity to an area of relatively low pressure, a gale will result, and so a storm may be due just as much to the rise of the barometer in one region as to its fall in an adjacent district. For the same physical reason, however, that the eddies in a river extend downward, and the water does not pile itself up in a peak, the normal disturbance of atmospherical equilibrium is the appearance of one of these vortices with pressure decreasing rapidly toward the center. ”

“ The illustration has often been used that meteorologists, in issuing storm-warnings, and having to estimate the direction and rate of motion of every storm the instant it shows itself in their neighborhood, are in the position of astronomers expected to assign the path of a comet from the first glimpse they get of it through a break in a cloud—a problem which all will allow to be impossible of solution. ”

“ It is, therefore, pretty clear that these warnings have not, as yet, proved themselves to be of much practical utility to our coasting trade and our fishermen. The question is a most interesting one, and although a satisfactory solution of it has not been attained, we need not despair; but we should attack it from the scientific side, and discuss the results in a calm, dispassionate spirit, and through some other medium than that of letters to newspapers. ”

“ This explanation of wind-motion is almost the only new principle which has been recognized in our science during the present generation, and its practical importance is daily forcing itself more and more into public notice with the development of weather telegraphy. ”

“ I shall commence by saying that a greater mistake can not be made than to assert that all storms are distinctly connected with cyclonic disturbances.
The force of the wind depends on differences of atmospherical }} pressure over a given area, and the only reason why storms are generally associated with cyclones is that these systems afford us the most serious instances of disturbances of atmospheric equilibrium, and consequently of differences of pressure, which are met with on the globe. ”

“ In every case the cyclone moves with the prevailing wind along its track.
Unfortunately, we know very little about the rate at which these storms advance, some of them moving at the extraordinary speed of fifty or sixty miles an hour, as for instance that of March 12, 1877; while others, like the West India hurricanes, do not attain one fourth of that rapidity of translation. It is remarkable that the rate of progress bears no relation to the intensity of the storm, the slow-moving tropical hurricanes being infinitely more violent than many of our rapidly-moving disturbances ”

“ As we have not been able to produce evidence of the birth of a storm, so have we never been lucky enough to find any one who was in at the death. In fact, some French meteorologists have hazarded the statement that storms can travel all round the world until at last they travel off it. ”

“ Wherever there is a rapid decrease there is a steep gradient, and consequently a strong wind.
Defining the term cyclone, in its very widest acceptation, as indicating a region of diminished pressure, round and in upon which the air is moving along paths which are more symmetrical all round the center the more perfect is the circular form of the system, we must at once see that not every cyclone is accompanied by a storm. ”

“ If the amount of change in the pressure or of rise and fall of the barometer during the preceding night be plotted every morning on such a chart, it is found that the path of the system for the day does not lie directly toward the region where the greatest fall has occurred during the night, but is regulated to a certain extent by the direction of the line drawn from the point of greatest fall to that of greatest rise. ”

“ The experience of those who have studied cyclone tracks in northern Europe shows that in winter, on an average, a cyclonic disturbance visits some parts of those regions every fourth clay, so that, if a warning were announced once a week regularly, there would be nearly a certainty of some sort of a fulfillment. ”

“ Another theory of storm-motion, strongly held by those who attribute all our storms to condensation of vapor, is that the track of the depression is always directed toward the region where the air is dampest. ”

“ A third theory of the origin of these storms is that which is strongly urged by M. Faye, in Paris, and is to the effect that, as interfering currents in rivers give rise to vortices which extend from the surface downward into the water, so all our water-spouts, trombes, and even the largest tropical hurricanes must be all formed in the upper regions of the atmosphere, and extend downward to the earth: the force which gives them their onward motion being supplied by the upper currents. ”

“ Modern meteorologists, however, almost with one voice, declare for a spirally incurving movement as the most probable behavior of the wind, as would be indicated by the angle which its direction makes with the isobars as just explained ”

“ During that interval thirty-six areas of depression were traceable across the Atlantic, that is, at the rate of eighteen a year. Testing these by wind reports from England alone, he finds that the chance that a storm center coming from the United States will strike England is only one in nine; of its causing a gale anywhere near the English coast it is one in six; while the chance of its causing a strong breeze is an even one. ”