Editing Stephenson's Rocket (section)

=== Firebox ===

The firebox was separate from the boiler and was double walled, with a water jacket between them. Stephenson recognised that the hottest part of the boiler, and thus the most effective for evaporating water, was that surrounding the fire itself. This firebox was heated by [[thermal radiation|radiant heat]] from the glowing [[coke (fuel)|coke]], not just [[convection]] from the hot exhaust gas.

Locomotives of ''Rocket''{{'}}s era were fired by [[coke (fuel)|coke]] rather than coal. Local landowners were already familiar with the dark clouds of smoke from coal-fired stationary engines and had imposed regulations on most new railways that locomotives would 'consume their own smoke'.{{sfnp|Snell|1973|p=59}} The smoke from a burning coke fire was much cleaner than that from coal. It was not until 30 years later and the development of the long firebox and [[Firebox (steam engine)#Brick arch|brick arch]] that locomotives would be effectively able to burn coal directly.

''Rocket''{{'}}s first firebox was of copper sheet and of a somewhat rectangular shape from the side.<ref>Richard,&nbsp;Gibbon.&nbsp;Stephenson's Rocket Manual: 1829 Onwards.&nbsp;United Kingdom,&nbsp;Haynes Publishing UK,&nbsp;2016.</ref> The throatplate was of firebrick, possibly the backhead too.{{sfnp|Snell|1973|p=61}} When rebuilt around 1831,{{sfnp|Snell|1973|p=61}} this was replaced by a [[wrought iron]] backhead and throatplate, with a drum wrapper (now missing), presumed to be of copper, between them. This gave a larger internal volume and encouraged better combustion within the firebox, rather than inside the tubes. These early fireboxes formed a separate water space from the boiler drum and were connected by prominent external copper pipes.