The calms of the Canary Islands

“The inland part, or centre (Gran Canaria), is exceeding high, and full of lofty mountains, which tower so far above the clouds as to stop the current of the north-east wind that generally blows here; so that when this wind blows hard on the north side of the mountains, it is either quite calm on the other side, or a gentle breeze blows upon it from the south-west. These calms and eddy-winds, occasioned by the height of the mountains above the atmosphere, extend twenty or twenty-five leagues beyond them, to the south-west. There are calms beyond or to the leeward of some of the rest of the islands as well as Canaria; for those of Tenerife extend fifteen leagues into the ocean; the calms of Gomera, ten; and those off Palma, thirty.

I have been frequently in all the calms of the islands, excepting those of Palm; and from my experience of them, I may venture to say, that it is extremely dangerous for small vessels, or open boats to venture within them, when the wind blows hard without. It is true, indeed, the wind raises the waves of the sea to a mountain high; yet those waves follow each other in a regular succession; for were they to fall confusedly one against another, no ship would be able to sail on the ocean. But in a storm, the wind driving the sea before it, each wave gives place to the one which follows; whereas in the calms of the Canary Islands, the sea not moving forward in the same direction with the sea without; and this resistance causes them to break just in the same manner as the billows break upon the sea-shore, but with less violence on account of the different nature of the resistance. This breaking of the waves is only on the verge of, or just entering into the calms, for within them the water is smooth and pleasant.”

George Glas