above the surface of the explosive, then the letters on the plate would also be raised above its surface. In 1894, Munroe constructed his first crude shaped charge: Among the experiments made ... was one upon a safe twenty-nine inches cube, with walls four inches and three quarters thick, made up of plates of iron and steel ... [W]hen a hollow charge of dynamite nine pounds and a half in weight and untamped was detonated on it, a hole three inches in diameter was blown clear through the wall ... The hollow cartridge was made by tying the sticks of dynamite around a tin can, the open mouth of the latter being placed downward. Although Munroe's experiment with the shaped charge was widely publicized in 1900 in Popular Science Monthly, the importance of the tin can "liner" of the hollow charge remained unrecognized for another 44 years. Part of that 1900 article was reprinted in the February 1945 issue of Popular Science, describing how shaped-charge warheads worked. It was this article that at last revealed to the general public how the United States Army Bazooka actually worked against armored vehicles during WWII. In 1910, Egon Neumann of Germany discovered that a block of TNT, which would normally dent a steel plate, punched a hole through it if the explosive had a conical indentation. The military usefulness of Munroe's and Neumann's work was unappreciated for a long time. Between the world wars, academics in several countries Myron Yakovlevich Sukharevskii (Мирон Яковлевич Сухаревский) in the Soviet Union, William H. Payment and Donald Whitley Woodhead in Britain, and Robert Williams Wood in the U.S. recognized that projectiles could form during explosions. However, it was not until 1932 that Franz Rudolf Thomanek, a student of physics at Vienna's Technische Hochschule, conceived an anti-tank round that was based on the hollow charge effect. When the Austrian government showed no interest in pursuing the idea, Thomanek moved to Berlin's Technische Hochschule, where he continued his studies under the ballistics expert Carl Julius Cranz. There in 1935, he and Hellmuth von Huttern developed a prototype anti-tank round. Although the weapon's performance proved disappointing, Thomanek continued his developmental work, collaborating with Hubert Schardin at the Waffeninstitut der Luftwaffe (Air Force Weapons Institute) in Braunschweig. By 1937, Schardin believed that hollow-charge effects were due to the interactions of shock waves. It was during the testing of this idea that,