At Easter 1902 I had sat my final college examination, and was now studying mathematics. This was not simple for me: Although one can see what follows from certain algebraic manipulations, why would this be done? “By mathematics, you are convicted, instead of convinced”, according to the philosopher Schopenhauer. After some time, I realized that, for me, mathematics was a collection of tricks. While my friends were busy with ions, with electrons, the Zeeman-effect and more, I stayed with the basics, with questions relating to philosophy and psychology, and remained unsatisfied. Accordingly, I changed to astronomy, but this was too subtle, and I continued with physics finally. I was asked to work on inhomogeneous waves generated due to total reflection in a second medium, as a Ph.D. topic. This was of interest to Prof. Voight but not to me! I continued with Prof. Prandtl and submitted a Ph.D. thesis on boundary layer flow in July 1907. I also added two or three cases for his theory. He told me after the exam that I hadn’t known all that he wanted. But he said that what I knew I had understood, and I was satisfied.
I stayed for a short period with Prandtl as an auxiliary assistant, and then moved to (Preussische) Versuchsanstalt für Wasserbau und Schiffbau at Berlin, where I worked on fluid friction in pipe flow, among other topics. In addition, I also submitted scientific works, such as on flow around wings and turbine blades using complex variables. All this was unprofitable, without success. I tried to continue working in turbulence, again without success, and finally told myself: “You are not a scientific.” Also, I admit that I did not have enough interest in the subject, but more for the approach. Prandtl was slightly disappointed because I was not interested in his wind tunnel, nor did I drive to the Rhön valley to glide model airplanes. I was asked why I did not look for a position as a professor. Evidently, you dream of this position as a student, and maybe I would have made it. At Aachen, I once achieved second ranking. My friend Barkhausen wanted to propose me for Dresden university, but I answered: “Let it be, I would disappoint you anyway!” Also, I was no more interested in science than before, and I do not regret it to this day. I feel my place is here at the engineering college. In any case, when you decide not to strive for the top position where you could have problems, choose the second position, where you can really add to progress. Therefore: “Blasius, who once worked in science, has been dead for a long time.” It was good having once been a physicist, but now I am a teacher, not corresponding to a scale model of practice but to its foundation.At Easter 1912, I started at Hamburg engineering college. After the war, which I survived without harm, I started with my books. I wanted to present a heuristic approach by accounting for the three impressions of the human mind: perception of ideas, elaboration of methods, and description of phenomena. Learning, working and order are thus the three essences of the mind. From 1920 to 1930, I mainly collected examples to present the basics of a problem. Finally, the heat transfer book appeared in 1931 (Blasius 1931), and then three booklets on mechanics by 1935 . At the age of almost 78 years, Blasius (1961) published a work on lubrication.
Blasius written in a letter in 1962 through correspondence of his wife Mrs. Elfriede Blasius.
I distinguish between exact knowledge and learning. As a good teacher, you should allow students to use their notes during exams, and ask questions on their integral knowledge. My concern is specialization, and – forgive me – the present trend in increasing lectures in other branches enhances this. Finally, consider our students: Precious people often interested in knowledge. Certainly, they would also like to earn money, but by working. They are willing to learn; care for them, for they trust you and are devoted to advance! Why at the end I am still here? Certainly not because of interest in the subject or because of money. The only reason I stayed for so long is because of my affection for youth, whom I should like to help in solving problems, and to assist into a profession. Here I am, and here I stay, until I am thrown out!
Some pictures of Blasius
Blasius portrait. 
Blasius playing chess. 
In the lecture hall 
Lecturing