Plot: Birmingham Botanical Gardens may seem an unlikely place to explore the wonders of the Industrial Revolution, but hidden behind its fragrant borders Guy Martin finds a hidden world of hi-tech Victorian engineering, show-off architecture, intrepid plant-hunters scouring the furthest corners of the Empire, and city fathers terrified of the 'degenerate' urban poor. As Guy helps to get the gardens back into shape, he tries to learn one of the Industrial Revolution's most skilful and dangerous jobs: blowing glass for the gardens' enormous greenhouses