In order to see what the connections between these ever-present, daily phenomena are, and their connection with other phenomena, and that we may understand their normal conditions, I will trace them approximately in a diagram (figure [17].)
The foregoing diagram of the daily phenomena of a summer’s day, when no disturbing causes are in operation, no storm existing within influential distance, and no unusual intensity or irregular action of any of the forces present, affords a basis for considering the various phenomena of the weather in all its changes and conditions.
It is obvious that the other phenomena do not all depend upon temperature merely, if indeed any of them do.
Temperature has but one maximum and minimum, and that is exceedingly regular, and does not correspond with any other.
The barometer has two; electric tension, two; magnetic activity, two; condensation, two—one the formation of cloud, and the other the formation of fog and dew; wind, one—resembling temperature in that respect, but embracing a much less period.
Fog forms at one barometric minimum, and cloud at another.
Fog forms at one period of the magnetic variation, cloud at another.
The formation of cloud corresponds with the greatest intensity of magnetic action, and its associate electricities. But the oscillations of the barometer do not correspond with either. And thus, then, we connect them:
| CAUSE. | EFFECT. | EFFECT. |
| Increase of magnetic or magneto-electric activity, as shown by declination and increase of horizontal and vertical force. | Decrease of pressure. Of positive electric tension. Of surface condensation, i. e., fog and dew. | Increase of primary condensation. Of wind. Of electrical disturbance and phenomena in the trade and its vicinity. |
This connection is equally obvious if the order is reversed—thus;