Show forefathers OF RADIO by GEORGE LEWIS of the crowley 1 developments in radio transmission went ahead by leaps and bounds but the reception of signals was hampered by the lack of proper means for detecting them many men worked upon this problem J A fleming for instance invented the valve which was the forerunner of the radio tube developed by deforest in this country but the detecting device which became roost most popular in the early days of radio was the crystal detector detec for ns as developed by denwoody and picard and introduced in 1000 1900 by means of tile crystal d detector the received elec dec J A fleming trie current Is so modified that it win will operate a telephone receiver up to this time had been so few radio stations that thore there wit was 9 little difficulty about the signals tit ot more than ow one station being received at the same time and interfering with one another however such were anticipated fly by other factors which overcome overcame them the length of waves sent out b tile the transmitting station depends upon certain constants of the appa apparatus ratu just at ar tile the length of a water wave wava depends upon the lie object which causes the disturbance in tile water and la Is re for the waves thu a 0 corl dropped into a pont pond will send out little short choppy waves while if a big ocean liner overturns the splash it makes will be followed by glant giant waves of great length uy by adjusting certain parts of the transmitting uppa ratus the length of wave that it sends out may bo be controlled and by adjusting similar parts of lie ho receiving up ap peritus one may control tile the wave length to which it will respond this adjustment la Is called 11 tuning 11 thus very early in the history of radio transmitting stations near each other were tuned to different wavelengths so eo that the operator of a rl re delving set could tune to uny tiny one of bt them |