CHAPTER XXV.

GUN-CARRIAGE--IRON SHIPS--HYDRAULIC CRANE--ICE MAKING--DRAINAGE OF HOLLAND--CHAIN-PUMP--OPEN-TOP CYLINDER--HAYLE HARBOUR--PATENT RIGHTS--PETITION TO PARLIAMENT.

Trevithick's description of gun-carriage and iron ship--Select committee--Glasgow iron-ship builders--Trevithick's comparison of gunpowder and steam--Cranes worked by air or water--Artificial cold--Liberality--Holland--Drainage--Dredging--Zuyder Zee--Hydraulic crane--Dutch pumping engine--Chain-pump--Haarlem Lake--Rhine--Windmills--Hayle Harbour--Disputed pole-engine patent right--Petition to Parliament, 1828--Marine boilers--Steam pressure--Engine duty--Lords of the Treasury refuse the petition--Davies Gilbert's views--Marine compound engine of 1871 Page 284-314