Jagadish Chandra Bose (1858–1937) was an Indian scientist who contributed significantly to various fields of research. He is well-known for his work on microwave-based wireless data transfer. He also developed a gadget known as a crescograph, which could detect extremely minute movements within plant tissues. The invention that got him most attention from outside India was his method for detecting poison gases. He proposed using magnets to pull metal ions from the blood into two separate tubes connected by a junction box, one tube containing a solution of chlorophyll and the other filled with flowers. The presence of gas in the test tube would cause a color change in the solution. He started his career as an assistant professor at Calcutta University but was soon promoted as a full professor. In 1897, he became head of the Physics Department at Presidency College, Calcutta. In 1906, he was appointed director of the Government Wireless Station at Dum Dum. There he designed a radio transmitter called "Radiajji". The radio waves it sent out were used by scientists around the world to study nature's invisible forces. He moved to England in 1914 to take up a position at Cambridge University but returned to India after just over a year because of political tensions between Britain and Germany. At the end of World War I, he proposed building a series of radio stations across Asia to communicate information about earthquakes that might affect shipping routes.