These results are suggestive. For instance, the energy of the upper half of the mass of the atmosphere, or that portion which lies above 18,000 feet, has been calculated to possess six times the energy of the lower half in which we live, and as yet, none of this enormous store of energy is applied to the use of man. While it appears certain that no navigable balloon or flying machine will ever be able to stem the enormous velocity of the upper atmosphere, rarified though it is, perhaps in the future aÎrial machines will take advantage of the prevailing currents of the high atmosphere, as our sailing ships do of the trade winds. The observations of cirrus clouds in various parts of the world show that they always move from a general westerly direction, while below this primary drift toward the east occur the relatively permanent or transient differences of pressure which cause the deviations from the normal circulation of the atmosphere, and give rise to the local circulation in storms. In the familiar daily weather map it will be noticed that there is usually some portion marked "low," and another portion marked "high." The former is an area of low barometric pressure, into which the winds at the ground blow spirally inward in the opposite direction that the clock hands turn; the latter is an area of high barometer, out of which the winds at the ground blow in the contrary way. The former when well developed are called "cyclones," and are usually accompanied by stormy weather, and the latter, called "anti-cyclones," bring fair weather. From the observations of the directions from which the clouds move in cyclones and anti-cyclones, we have found that above the cumulus level (at the height of about a mile) the inward inclination of the wind in a cyclone, and the outward inclination in an anti-cyclone, both disappear, and the general drift from the west prevails. The results of the observations are shown in Plate V., Atmospheric Circulation in Cyclones and Anti-cyclones, representing sections of the atmosphere, concentric to the earth's surface, in the five cloud-levels seen from above. The arrows fly with the wind and are proportional in length to its velocity, the dotted arrows indicating the probable flow of the air through the cyclones and anti-cyclones that are indicated by the circles, their axes being assumed to be nearly perpendicular to the earth's surface. Above the cumulus it will be observed that the wind in the cyclone tends to come from the south-west in front and from the north-west in the rear, while in the anti-cyclone the contrary is the case, indicating a deflection of the westerly upper current to the right in cyclones and to the left in anti-cyclones. This sustains the theory that the cyclonic circulation is struggling against a general atmospheric drift from the west which increases with altitude, and above the height of a mile becomes greater than the cyclonic influence. Higher than this, the atmospheric circulation is