Mining demand, boilers, and manpower pressure

Early engines found buyers in mines, where pumping created an immediate market for mechanical power. Their development coincided with Napoleonic-era Britain, when supplying a large navy and army increased resource demand while manpower remained limited. That pressure encouraged machinery that could make existing labor more productive. Fire-tube boilers passed hot gas through tubes immersed in water, while water-tube boilers passed water through tubes surrounded by hot gas. Water-tube arrangements became more common at sea, although exceptions were common. Marine steam therefore has to be understood through fuel, labor, boiler practice, and operating environment together.