The People of Gibraltar
1842 - The Devil's Bellows – By Voluntary Labor

Originally the Devil’s Bellows may have been the name of a ravine that separates the upper slopes of the Rock from the southern plateau of Windmill Hill Flats. Later it probably became the name of the tunnel that leads to the entrance to Windmill Hill from the north. One can get to it by climbing up the Devil’s Gap. (See LINK) The name derives from the fact that it is a naturally windy place facing the open south. The funnel like entrance and exits act as funnels. 

( 20th century )

At the time of writing there is a plaque on the wall beside the tunnel that reads :
“AD 1842. The roads were made and the surface levelled of this heretofore rugged hill by the voluntary labor (sic) of Her Majesty’s VII th Royal Fusiliers”.
There is no indication of whether that “labor” included the building of the tunnel itself. 

One early mention of the Bellows is that of Dr John Hennen. (See LINK) Hennen was quartered in Gibraltar for the best part of 1809 to 1828 when he died of the very same yellow fever (see LINK) that he had been sent to report on as the Garrison's Medical Superintendent. Included in Sketches of the Medical Topography of the Mediterranean published in 1830 is the following reference to Gibraltar’s Devil’s Bellows.
What is called the Devil's Bellows on this hill, is a striking illustration of the effects of long drawn passages, or funnel-shaped chasms, in producing partial currents of wind ; and in common with other exposed situations, is evidently conducive to the production of all those pulmonary and bowel affections commonly referred to suppressed perspiration. Several severe cases of fever have occurred among the troops and their families quartered on this hill, which appear also to owe their origin to this cause.

Windmill Hill looking north towards Windmill Hill Barracks – The Devil’s Bellows would have been on the extreme left of the picture    ( 1835 – H. E. Allen )  (See LINK) 

Francis Elizabeth Davies (see LINK) in her Memories of Gibraltar published in 1841 writes:
And then, for its localities, what strange and satanic sobriquets! His demoniac majesty claims there so many extraordinary possessions, that he may justly be supposed to be lord of the manor. There are the ‘Devil's Bowling-green,’ the ' Devil's Gully,’ the ‘ Devil’s Bellows,’. . . 
R. Stewart Patterson (see LINK) in Notes and Queries for Literary Men published in 1884 also mentions the site.
The Devil's Bellows, a small valley enclosed amongst the fortifications at the entrance to Windmill Hill barracks and the military prison. On a stormy day the wind rushes with great violence through a tunnel here and sweeps down the defile.
Map showing the location of the Devil’s Bellows   ( 1885 – Richard Ford – Handbook for travellers in Spain )  (See LINK)

Another map in which the Devil’s Bellows makes an appearance    ( 1977 – Don Gifford and J Seidman’s Notes for James Joyce’s Ulysses which was written 1918-1922

The entrance from the north to the Windmill Hill area  with Lathbury Barracks in the background  ( 20th Century )