The main goal of the two books “The Theory of perspective demonstrated” is to teach readers about the theory of perspective and help understanding it, by demonstrating everything with drawings. To achieve the demonstration, the author gives a very clear and structured description about the doctrine of planes and the doctrine of planes applied to the principles of perspective and through references to the second book, where John Lodge Cowley has drawn the according figure to the description, the definition is also demonstrated.
The first book is very structured, which helps to understand what it is tried to demonstrate and describe. Except from the main titles, in which very different font sizes are used, the text is very plain. On the top of every page, the name of the part is written. Part I and II are structured very similarly. In the definitions itself are a lot of numbers, roman numbers, and letters. They all help to understand the demonstration of the definition which is found in the second book. For every definition Lodge puts a roman number and if there is a Figure in the second book about the Definition it is shown through “Illustration” and then the number of plate and Figure, so the demonstration is easy to find. The text seems to be mirrored in the middle of the book, also the page numbers are mirrored. The Text is closer to the middle of the book then to the outer edge.
The pages seem to be very thin because it is possible to see the print from the other side of the page.
The second book is purely the demonstrative part. There is no written text but the identification of the figures. Some figures are not aligned with the pages and oblique for no reason it appears. A few figures additionally have threads made into the page. On the backside of those pages the knots fixing the threads are seen. There are more empty pages then used ones. It seems they can be used for the readers own sketches and notes to understand the demonstration even better.
For a full understanding of the information in the book it is necessary to work with both books at the same time. In the first book the whole Information is written down with the numbers and letters referring to the specific line inside the according demonstration figure. Looking at just one of the books lets it appear very complicated and complex.
Figures, threads, definitions