Letter from J [John] Herschel, Brompton Barracks, Chatham, to 'Dear Papa' [John Frederick William Herschel] He has attended lectures by Mr [John] Anderson of Woolwich on hydraulics and the steam engine, and by Mr [William Thomas] Doyne formerly of the Works Corps on civil engineering. His plan and translation is almost complete, but he has had to devote time to practical operations. He has been inspecting the construction of saps and mines by the men, using a large plot of land for the purpose. He describes their work and timings for climbing ladders. 3 March 1857