Storms, Lightning, and All the Other Fires that Ignite in the Air

Winds are created when the clouds dissolve into vapors.

The clouds can also sometimes descend so suddenly that they drive away violently all the air that is under them. This creatse a very strong but short-lived wind.

This is similar to a veil spread high in the air, then letting it descend flat towards the ground.

Heavy rains are almost always preceded by such a wind, which acts from top to bottom.

The wind’s coldness comes from those rain clouds, where the air is colder than that around us.

This wind:

• causes swallows to fly very low, warning us of rain.
• brings down gnats which the swallows eat.
  • Those gnats are used to fly in the high air when the weather is fine.
• roars down chimneys making the ashes in the corner of the fire in the fireplace dance
  • The fire becomes excited and create little whirlwinds

The descending cloud is very heavy and extensive especially over large seas because the vapors are very evenly dispersed there.

• This is why, as soon as the slightest cloud forms in some place, it immediately extends in all the other neighboring ones.
• This infallibly causes a storm which is stronger, the larger and heavier the cloud is.

It lasts all the longer, the farther the cloud descends.

The Indian Ocean

These squalls are made of those clouds which sailors fear so much in their great voyages, especially a little beyond the Cape of Good Hope.

There, the vapors that rise from the Ethiopian Sea, which is very wide and very heated by the sun.

They can easily cause a downwind stopping the natural course of the wind coming from the Indian Sea.

• It assembles them into a cloud.

The inequality between these 2 large seas and this land causes that cloud to become much larger than those which form in other regions where there are lesser inequalities between our plains, lakes, and mountains.

Almost no other clouds are ever seen in these places.

As soon as the sailors there perceive some clouds which begin to form they hasten to lower their sails, and prepare to receive a storm, which always follows immediately.

• This is even if the clouds are so small ant the rest of the air seems very calm and very serene

I think that this storm will be greater, the smaller this cloud was at first.

This is because it was not able to become thick enough to obscure the air and be visible.

This means that it was at an extreme height and distance. The higher a heavy body ascends, the more impetuous its fall.*

Thus, this cloud being very high suddenly becomes very large and heavy. It falls entirely, violently driving away all the air under it, causing the wind of a storm.

The vapors, mixed among this air, are dilated by its agitation. Vapors also come from the sea from the agitation of its waves.

This:

• greatly increases the strength of the wind
• delays the descent of the cloud, making the storm last longer.*