^"Dürr water-tube boilers". William Allan MP. Parliamentary Debates (Hansard) (House of Commons) 92. col. 907. "Eight water-tube boilers of the Durr type have been ordered from Germany. The total cost of the boilers is £19,450. This is exclusive of spare parts and fitting on board. The boilers are to be placed on board H.M.S. "Medusa." They have been guaranteed by the maker to give 155,000 lbs. dry steam per hour from feed water at 80 deg. F., with an air pressure of 1½ inches; 104,000 lbs. per hour with ½ inch air pressure (that used for continuous steaming); and 80,000 lbs. per hour with natural draught."