Mitrailleuse
The first "mitrailleuse" was a manually fired 50-barrel volley gun originally developed in Belgium in 1851 by the Belgian Army Captain Fafschamps, who made a rough prototype and drawings of his invention. The system was improved during the 1850s by Louis Christophe and the Belgian engineer Joseph Montigny, with the completion of the 37-barrel Montigny mitrailleuse in 1863. From 1859, Joseph Montigny proposed his design to Napoleon III, which led to the development of the French Reffye mitrailleuse, designed by Jean-Baptiste Verchère de Reffye with the collaboration of Montigny, and which was adopted by the French Army in 1865. Initially kept under wraps as a secret weapon, it was widely used in battle by French artillery during the Franco-Prussian War (1870–71). Smaller numbers of other designs, including the Gatling gun, were also purchased by the French government during the latter part of that conflict. The Reffye model had initially been built in small numbers and in secrecy: only about 200 were available at the beginning of the conflict. This also kept regular French field artillery in a neglected position in the eyes of French emperor Napoleon III, with dire consequences during the Franco-Prussian War of 1870–71.
Microwave
The first powerful sources of microwaves were invented at the beginning of World War 2: the klystron tube by Russell and Sigurd Varian at Stanford University in 1937, and the cavity magnetron tube by John Randall and Harry Boot at Birmingham University, UK in 1940. Britain's 1940 decision to share its microwave technology with the US (the Tizard Mission) significantly influenced the outcome of the war. The MIT Radiation Laboratory established secretly at Massachusetts Institute of Technology in 1940 to research radar, produced much of the theoretical knowledge necessary to use microwaves. By 1943, 10 centimeter (3 GHz) radar was in use on British and American warplanes. The first microwave relay systems were developed by the Allied military near the end of the war and used for secure battlefield communication networks in the European theater.