William Maginn was a British officer of the line who wrote The Military Sketch Book - Reminiscences of Seventeen Years in the Service Abroad and at Home in 1827. A two volume affair, it dealt mostly with his experiences during the Peninsular war and other postings.
A few years later he wrote several 'Letters from Gibraltar' which were published in 1830 in the United Service Journal and Naval and Military Magazine. He was thirty odd years old, probably unmarried and was lucky to have arrived a year or so after the 1828 yellow fever epidemic. ( see LINK )
The Rock ( 1830s - J.M. Van Braam - Detail )
For those ready to face his opinions on what the Rock was like in the early 19th century - or at any rate what it was thought of by one particular officer of the Garrison - the following are the individual links to the last five of his Letters from Gibraltar. The first two seem to be unavailable on the net.
Letters from Gibraltar 3 - Speak of the Dead!
Letters from Gibraltar 4 - Cleaner than Bath
Letters from Gibraltar 5 - Sebastiano
Letters from Gibraltar 6 - 'Corréo de Toro'