Between the equator and latitude 30 deg.

or 40 deg.

there is a difference of six minutes in the rotation period--i.e., the equatorial parts turn round the axis so much faster than the parts north and south of them, that in one rotation they gain six minutes of time.

In other words, the clouds over Jupiter's equator flow past those in the middle latitudes with a relative velocity of 270 miles per hour.

But there are no sharp lines of separation between the different velocities; on the contrary, the swiftness of rotation gradually diminishes from the equator toward the poles, as it manifestly could not do if the visible surface of Jupiter were solid.
In this respect Jupiter resembles the sun, whose surface also has different rates of rotation diminishing from the equator.