Gerard at Punta de Arenas, in the Pacific, in 1822--Nicolas Castro worked a gold mine, 1821--Alverado's ore-grinding machine, 1822--Climate of Costa Rica--Mines in the Cordillera--Canal from the river Machuca to Quebrada-honda--Castro's mine--Padre Arias, or the Priest's mine--Trevithick and Gerard's proposal for iron railroads, &c., for the mines of Costa Rica, 1827--New line of road from San Juan, on the Atlantic, to the Costa Rica mines--Serapique River navigable--Trevithick's diary--A mule track easily constructed--Comparative distance to the mines from the head of the Serapique on the Atlantic, and Punta de Arenas on the Pacific--Trevithick nearly drowned in the Serapique--Nearly starved before reaching San Juan--Performs a surgical operation--Designed the locomotive between breakfast and dinner--Robert Stephenson and Trevithick at Carthagena--Nearly drowned in the Magdalena--Saved by Mr. Bruce Napier Hall--Trevithick nursed Robert Stephenson Page 260-275 CHAPTER XXIV. RETURN TO ENGLAND. Bodmin School, 1827--Cube root--Trevithick's reception--Saving in Cornish mines--Model gun--Gerard's return, 1827--His meeting Robert Stephenson--His remarks on Costa Rica--Montelegre's search for a better line of road--Mr. M. Williams's proposal--Change of Ministry, and the gun-carriage--Model of iron packet-ship and engine--Robert Stephenson's remarks on mining--Trevithick's rejection of purchase-money Page 276-283 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 CHAPTER XXVI. TUBULAR BOILER--SUPERHEATING STEAM--SURFACE CONDENSER.