The original copy of P. F. Blackman's 1956 thesis, submitted for the Degree of Ph.D. in Engineering of London University.

This bound book is hand-typed, with hand-drawn diagrams, and black-and-white photographs pasted in. A copy of the thesis summary is provided below:

"Certain important aspects of closed-loop system and network analysis are closely related to complex variable mathematics. Graphical interpretation of such analysis is frequently employed owing to the difficulty of exact analytic work. In particular the 'p-plane' or 'root-locus' method is essentially simple, and affords considerable insight into the problem, but becomes tedious in practice for complicated systems, and several instruments have been devised to reduce the labour.

"It seemed to the author that the application of p-plane principles could be considerably extended if certain operations beyond the scope of existing instruments, particularly manipulation of ept, and summation of real and imaginary components of vector products, could be achieved. These facilities would enable more advanced types of problems to be handled, such as systems containing a pure delay, and transient response by contour integration, and would permit investigation of problems not previously considered.

"This Thesis gives proposals for a Computor to provide these additional facilities. In principle the proposals are that the techniques should be as simple as possible compatible with accuracy to engineering requirements, while facilities provided should be just adequate to eliminate excessive labour from investigations. This leads to a suggested combination of analogue and digital principles.

"An experimental Computor developed from these proposals is described. Vectors are represented by AC voltages, final results being presented as counts on Dekatrons. The Computor is largely relay controlled, and accuracy is of the order 1%-2%.

"The thesis contains 3 sections:-

"Section 1. Outlines the p-plane method, and gives proposals for the Computor. The design of a proposed resistance network analogue of the complex plane is dicussed.

"Section 2. Describes the experimental Computor, and the essential points of interest in the analogue to digital conversion processes. The operation of individual units is outlined, more detailed information being given in an appendix.

"Section 3. Illustrates the varied type of problem that can be handled on the Computor, including some exaples involving time-varying zeros. Alternative applications for the Computor, and modifications resulting from operating experience are discussed."