Readers might like to compare the technological evolution of Camelod with the growth of Britain’s industry in the 18th century otherwise it may seem that the nation’s progress is far too fast.

In Camelod, Heron’s early atmospheric steam engine that developed from his hot air machines and the piston pumps and valves of Alexandrian origin, operated for the first time as a drop forge in 33 AD, thirty six years later it had evolved into a steam engine with double acting cylinders. This required the invention of lathes with slides for the tools (instead of hand held tools), boring machines capable of producing cylindrical bores of precise dimensions and fine finish; suitable steels and cast irons, development of boilers that were capable of sustaining forty to fifty pounds per square inch of pressure, blown hearths to fire the boilers. These matters themselves were supported by a host of other inventions that made them possible, such as the blast furnace, blowing engines, the choice of fuels from ‘hard’ coal to coke and so on.

A complex picture and a remarkable achievement in just thirty three years! Too remarkable, perhaps? Bound copies Now available from www.lulu.co

In Britain, Smeaton’s atmospheric engine had a crudely machined bore, but was two or three times more efficient than Newcomen’s cast bore. This was 1772, in 1776 Watt invented the condenser for the atmospheric engine. This was a large engine built into a structure of bricks, stone and timber and its bore was quite rough, with a rope wound piston to accommodate the lumps and hollows. The precision boring machine was invented the year before in 1775 and Watt’s engines improved greatly. All these engines simply stroked up and down and operated pumps - usually for mines. Double acting steam engines were invented in 1782

The first steam engine producing rotary motion appeared in 1785, it was double acting and operated on steam at forty pounds to the square inch. The steam boat with paddles came along two years later in 1787 as did the first cast iron barge for inland waterways. The wool combing machine was invented in 1789, rolling mills were powered by steam in 1790. In 1794 the ‘first’ hot air ballon ascended in France. !795 saw the first hydraulic press, metal piston rings in 1797, several side paddle boats in 1797, the lathe with metal slides and tool post in the same year.

Cayley flew in a heavier than air machine in 1799 (at least his coachman did) and the basis for aerodynamics was established (the Wright brothers gratefully acknowledged this after their own historic powered flight).

An industrial screw cutting lathe was in use in 1800 as was a fully ‘portable’ steam engine with a cast iron bed. The modern re-invention of mass-production appeared in the docks, producing pulley blocks by the tens of thousand in 1802 - this was a major reason for the superiority of the British navy during the Napoleonic Wars. Pulley making was a major bottleneck in making and maintaining ships and forty seven different machines were developed for the process. In 1804 a steam locomotive pulled ten tons of iron a distance of nine miles (that was the length of the track). Steam boats now had a speed of 5 mph.

This is a span of only thirty two years from Smeaton's crude engine, or twenty eight years after Watt improved it by external condensing, a little less than the span of fictional Camelod’s industrial expansion from an agricultural society with a small number of craftsmen, to a flourishing manufacturing nation. It was a period of phenominal growth in Britain and very shortly after in America and Europe - a time of intellectual excitement and endeavour before the hard grind of the Victorian age.

I have taken many liberties with dates in this series of ‘histories’ (the invasion by Rome was delayed by twelve months), but in general I have kept within what is known of the existing technologies of Alexandria and the Mediterranean, and what has been inferred (production of sulphuric acid, distillation by complex stills, and the use of lenses), mass-produced pottery, steel from India (Wootz steel) and much more. The stirrup, I must admit, was a bit of a leap, but I needed it - and so did Gregory.