Instrument maker John Merry Ronketti was born Giovanni Maria Ronchetti, in the village of Tavernerio, close to Como. Having settled in Holborn in 1780, he started in business producing artifial flowers and feathers, before becoming one of the finest stick and wheel barometer makers. Working from no. 180 Holborn, he was active between 1787 and 1797. From around 1790 to 1800 he worked in partnership with fellow immigrant Francisco [Francis] Pellegrino. Ronketti died in 1819. Several of his relatives have been recorded as working in Manchester and New York.