Nature’s Music. Consisting of Extracts From Several Authors: With Practical Observations, and Poetical Testimonies, in Honour of the Harp of Æolus (1808)
Bloomfield’s interest in music was of longstanding: he had, before marrying, been a fiddle player and he continued to write verse for composers to set. Many of his songs were arranged for piano and harp. It was not until 1806, however, that Bloomfield took up, as a trade, the manufacture of Aeolian harps, telling his friend Thomas Inskip that ‘I find such pleasure in the use of the saw and the plane that I am determined to … attack the Harps tomorrow’ (Letter 189; 27 June 1806). He gave harps to his genteel friends and sold them to their friends: Thomas Park, the editor, and his wife Maria Hester, were amongst the earliest to receive an instrument. Mrs Park then published a sonnet in thanks. Her ‘Addressed to an Eolian Harp, constructed by the Author of “The Farmer’s Boy”, “Wild Flowers”, &c.’ was published in The Monthly Mirror (21 (1806), 196):
The sonnet claimed the attention of Capel Lofft, who wrote alerting Bloomfield to James Thomson’s poetic tributes to the instrument, ‘the charming lines in the “Castle of Indolence”,’ and ‘his exquisite “Ode to the Aeolian Harp”‘ (Letter 188; June 1806). Thus edified, Bloomfield was able, in other letters, to make the instrument’s poetic heritage part of the package that would recommend it to his patrons and customers. Writing to the Earl of Buchan on 15 September 1806 (Letter 191) he declared
I cannot conclude without informing your Lordship, whom I know to be possessd of a love for nature’s music, and a fund of fancys, that I have lately taken up a new and most agreeable trade, that of constructing Eolian Harps. I am become rather dextrous in the use of the plane and the glue-pot, and find a demand that I am hardly able to satisfy. Can any thing in Nature, or even in imagination, exceed the tone of that simple instrument? Your unrivalled Thompson knew it well. Witness his Castle of Indolence, the finest lines that can possibly be written on the subject.Ah me, what hand can touch the strings so fine?Who up the lofty diapason rollSuch sweet, such sad, such solemn airs divineThen let them down again into the soul?
your idea of my being in the road to publish what I can gather as to the nature of the Harp, is wrong. I only thought of printing a few copies for private distribution to such of my customers as profess’d to know nothing on the subject, and just to make it pay its own expence, and stand as a profess’d compilation on that particular themes. It would save me much talking, and that to me is a material thing.
By September 1807 he had compiled a manuscript, only to lose it in a fire. Replacing it from his sources (it was drawn largely from a journal article and from Sir John Hawkins’s General History of the Science and Practice of Music), he gave a history of the instrument, a description of his own construction,  a theoretical discussion of its modus operandi and a brief anthology of literature concerning it. 
By the winter of 1807 ill-health and delays at the engraver had left Bloomfield seriously in arrears with his harp orders, and although the manuscript was printed by his friend James Swan in 1808 for distribution with each harp sold, production began to languish. It picked up in December 1808, when Bloomfield’s musical brother Isaac came to stay in London. ‘We are making Harps by the dozen’, Bloomfield recorded (Letter 234). This flurry of manufacture did not last, however, as Bloomfield succumbed to migraines, eye problems and rheumatism, and became plagued by poverty. His last mention of building harps comes in a letter of 1811. Nature’s Music also languished until in 1822, Bloomfield, by now in dire financial straits, wondered whether it might be reprinted, and perhaps form a means of raising money through subscription (Letter 365). This did not occur.