The first modern computers did not generally appear until around World War II, with devices such as the Z1 invented by Konrad Zuse in Germany in 1936, or the Turing Machine by Alan Turing, or the Colossus in 1943. However, the first general-purpose mechanical computer dates back much earlier than many would expect. It was the Analytical Engine, designed by Charles Babbage in 1837.
Charles Babbage was a man of many talents, and aside from being an inventor (Babbage was the inventor behind cow-catchers found on trains) he was also a mathematician, and had designed the Difference Engine in 1821 (also known as Difference Engine No. 1). The Difference Engine, despite being designed in 1821, was capable of calculating and tabulating polynomial functions. The device also included a printing mechanism that would allow the Difference Engine to print the results of its calculations into a table. However, it was not without its problems. There were three main issues related to the Difference Engine, which were the errors of calculation, errors of transcription, and errors of printing and typesetting.
To date, the Difference Engine is regarded as the first calculator, although Babbage himself never completed a working Difference Engine as construction began in 1830 until differences with the engineer ended construction in 1932, and then funding was totally cut ten years later. Had the device been completed, it would have had 25,000 parts, been eight feet tall and weighed roughly four tons. Also during the 1820’s Babbage had inspected multiple manufacturers throughout Europe, which led him to believe that the technology at the time was incapable of producing the intricate and precise parts required for the Difference Engine. Later on between the years of 1847 and 1849
While working on the design of the Difference Engine in 1834 after construction had stalled, Babbage began working on the a new device called the Analytical Engine. Whereas the Difference Engine was more along the lines of a mechanical calculator, the Analytical Engine was intended to be more of a mechanical computer. It was the design of the Analytical Engine that would cement Babbage’s fame as a pioneer in the development of computers. By utilizing punched cards, the Analytical Engine could be programmed similar to a system used for weaving intricate patterns in the textile industry. One of the most interesting design aspects of the Analytical Engine (which was shared with the Difference Engine) was how the memory device, known as the “Store,” was separated from the central processor, which was referred to as the “Mill.” Even today, modern electronic computers are organized in this way.
Unfortunately, Babbage only completed portions of the Difference Engine and never fully completed physically building it, as well as the Analytical Engine which only existed on paper. This is due to several factors, such as the disagreement between Babbage and the engineer during the building of the Difference Engine, the lack of suitable resources or precise-enough instruments, Babbage’s difficult personality, an eventual withdrawal of funding, as well as how Babbage’s ideas were simply to advanced for many to grasp. One individual, Augusta Ada Byron, was surprisingly aware of the effect the Analytical Engine could have on scientific advancement, and believed it could lead to things such as artificial intelligence, mathematical computation, and computer music. Augusta was one of Babbage’s most important supporters, as she not only understood the device and what it could achieve, but was also capable of explaining it to laypersons or average people in a way that Babbage could not.
Despite only completing the “Mill” portion of the Difference Engine and a trial portion of the Analytical Engine (which was unfinished at the time of Babbage’s death), Babbage’s Analytical Engine was a huge influence on computers today. As mentioned earlier, the concept of separating the storage unit, processing unit, and printing unit is adhered to in modern computers. There was also the concept in which Babbage would have used punched cards to program the device, and how Babbage is referred to nowadays as the “father of the modern computer.” In 2000, the Science Museum completed a replica of the Difference Engine utilizing only resources that Babbage himself would have had access to; the device was dubbed “Difference Engine No. 2.” There is also now a group called Plan 28 that is seeking to actually build the Analytical Engine using the plans and schematics left behind by Babbage, in order to create one for public viewing, as well as to illustrate the Babbage was essentially one hundred years ahead of his time.
Even though Charles Babbage never completed either the Difference Engine or the Analytical Engine, the effects his had on the future field of computers is astounding. One can only wonder at how the Analytical Engine may have affected the world had it been perfected and completed, and although many science-fiction writers claim the world could have become a steampunk-esque technologically advanced society trapped in Victorian-era culture, it is important to remember how much one man affected an entire industry one hundred years before it even existed.
For another pre-electricity invention from the 1800’s, try taking a look at this article about the Steam Man robot.
northatlanticblog 
Babbage’s concepts were astonishing. And the mechanical calculator-computer didn’t really come into its own until the Edwardian period – I am thinking of the Dreyer Fire Control Table in particular. Very complex and didn’t quite work in real time. But still in spirit the same sort of mechanical device as the Difference Engine.