Constructors: Mihailo Petrović Alas, Milorad Terzić
Manufacturer: Military Technical Institute in Kragujevac
Place and time of production: Kingdom of Serbia, 1910
Dimensions (cm): 5 . 4.5 . 6.3; 6.5 . 4.5 . 5; 5.5 . 2.5 . 4; Ø 6.5 . 5
Inventory number: Т:3.85
Distinguished Serbian mathematician, explorer, travel writer, musician and fisherman, Mihailo Petrović Alas (1868–1943), was also an inventor, interested in applied science and engineering ever since his student days. His innovative spirit was a good match for another one of his professions – military. In 1898, in Niš, he passed the exam for reserve engineering sub lieutenant. His whole life he has always diligently responded to the call of duty and he has worked on military issues first of all, because he felt obliged to his homeland.
Petrović has spent most of the First World War in Switzerland, as part of the Serbian embassy and adjutant to Prince Đorđe Karađorđević, working on codes. In 1941, he was once again activated, that time in the rank of reserve lieutenant colonel.
Therefore, it comes as no surprise that half of Petrović's patents had military applications. Petrović's first patent, field artillery rangefinder (French patent number FR 1413.730, titled Télémetre a sextant), which he protected in 1910, is particularly important. He constructed it together with the captain of Trigonometry section of the Geography Department of the General Staff, later General Milorad Terzić (1880–1939). The rangefinder has been designed for Military Technical Institute in Kragujevac and it has been manufactured in an unknown number of copies. Apart from Perpetual Calendar manufactured in Switzerland, rangefinder is the only Petrović's patent that was produced and applied. In 2004, the rangefinder was donated to the Museum by the Library of the Serbian Academy of Sciences and Arts.