Beyond the latitude of 30 deg., and as far as 40 deg., this purpose will generally be answered.
We are sufficiently familiar in England with the fact of westerly winds prevailing in the Atlantic.

From a list of the passages made by the New York sailing packets across the Atlantic, during a period of six years, it is shown that the average length of the voyage from Liverpool to America, that is, towards the west, was forty days; while the average length of the homeward passage, or that from west to east, was only twenty-three days.

And it may fix these facts more strongly in the recollection, to mention that the passage-money from England to America (in the days of sailing packets) was five guineas more than that paid on the return voyage.
This prevalence of westerly winds beyond the tropics is readily explained by the same reasoning which has been applied to the Trades blowing within them.

The swift moving air of the torrid zone, on being rarefied and raised up, flows along towards the poles, and in a direction from the equator, above the cooler and slower-moving air, which, as I have already described, is drawn along the surface of the earth from the temperate regions beyond the tropics.

When the rarefied equatorial air has travelled some thirty or forty degrees of latitude along the upper regions of the atmosphere towards the poles it becomes cooled, and is ready to descend again, between the latitudes of 30 deg.
and 60 deg., to supply the place of the lower air, drawn off towards the equator by the Trade-winds.