In this paper one of the rare physics books written in Serbian in the second half of the XIX century, when technical literature in our country was almost non-existent, is presented. The subject is a book written by Prof. Đorđe Stanojević Cosmic Energy and Modern Physics (Васионска енергија и модерна физика) printed in 1887 in Belgrade. Though small in size, it is very concise, informative and with a very clear style. The book is the printed form of the Invited Lecture delivered at the beginning of his engagement at the Military Academy so that it gives a review of achievements in natural sciences and technology in the late XIX century. The present article contains a parallel consideration of the achievements in natural sciences and technology in the beginning of the XXI century. Đorđe Stanojević’s Cosmic Energy and Modern Physics has been digitised and it is available at the Virtual Library of the National Digitisation Centre (Virtual library, http://elib.matf.bg.ac.yu:8080/virlib/). The digitisation of these books is a part of the project aimed at electronic archiving of Serbian books from the field of mathematics and natural sciences printed in the XVIII and XIX centuries.