Antiques Roadshow expert gasps 'my knees are shaking!' seeing rare item

One of the experts on Antiques Roadshow was left physically shaking after a guest presented him with a 'heart-stopping item' on Sunday's episode of the show. The revelation was made by antiques expert Mark Hill after he was presented with an 18th-century microscope during the show's stop at Hill of Tarvit in Fife, Scotland.