These drawings show the calculating mechanisms of the Analytical Engine during Babbage's first phase of work on it between 1833 - 1848. Most of the drawings show details of the mechanical sub-assemblies of the machine, such as carry mechanisms and counters. Other drawings show the physical arrangement of these sub-assemblies in a series of 'plans'. These plan drawings show the interconnections of the sub-assemblies and demonstrate some of the functional arrangement for the logical structure of the machine.
About 30 distinct 'plans' were developed between 1833 - 1848. Whilst Babbage's first phase of work on the Analytical Engine dates between 1833 -1848, the dates of the drawings start and end a year later, from 1834 - 1849.
- System of Arrangement: