While in Florence Barrow spent much of his time in the Medici Library where there was a great collection of coins. Barrow later used the expertise he had acquired to act as a collector of coins and medals for a London merchant who helped Barrow with much needed finance.
Habang sa Florence Barrow nagastos marami ng kanyang panahon sa Library na kung saan ang Medici doon ay isang mahusay na koleksyon ng mga barya. Barrow mamaya na ginagamit ang kadalubhasaan niya nakuha na kumilos bilang isang kolektor ng mga barya at medals para sa isang London merchant na tumulong Barrow sa maraming kailangan finance.