Maceroni opens the letter by writing of his admiration for Owen and his efforts "for the benefit of mankind".
He continues to write of a series of misfortunes which has befallen him - including being prevented from giving the use of his "inventions" to the Sultan of Turkey by the English Ambassador [to Turkey] and a "friend" spending some money which was owed to him, all of which has forced him to ask "several friends" for money, and hence asking Owen for the sum of £100.
Included is a printed copy of an article dated 20 Jan 1820 taken from the Mechanics Magazine and written by Maceroni. The article is entitled 'Discovery of the Art of Flying', and in it Maceroni claims to have invented some form of 'machine' to enable human flight, but explains that "circumstances" have made it necessary he sell a share "in it" for a small sum of money - £1500 giving rights to 1/4 share in the "honorary and pecuniary rewards".