The whole book is structured in 2 parts. The first one is the largest part of the book. It consists only of texts. The texts are divided into main 4 sections (Book l – IV) and are made up of several chapters. The second one presents illustrations of lighthouses and plans.
The first pair I chose shows the first section (Book I) changes into the next one (Book II).
The second pair shows the chapter change.
If you compare these two pairs, you will see the new section is put on the new page while the change of the new chapter is written on the same page. For me, this is something notable and it makes me feel (without having a look at the text exactly) the content in every section might consist of different topics that are independent on each other.
The third pair shows an illustration that is shown on the right-hand side. And on the other side, there is an empty page. It might be the page for drawing or making notes.