Who would ever have thought that tarnishing of silver would find a use? http://www.newscientisttech.com/article/dn8946-invention-drinkdriver-arm-scanner.html
Tuning for oil Wealthy oil companies are always looking for ways to save money and time, and this simple invention for finding underground oil reserves may help them do both. The usual practice is to take fluid samples from the ground and wait several weeks for lab analysis to confirm the presence of H2S (hydrogen sulphide) and CO2 (carbon dioxide), which signals a likely oil strike. The new idea, from oil company Baker Hughes - part of the Howard Hughes empire - is to make compounds near oil reserves literally sing out. Or, more accurately, sing out of tune. A vacuum cylinder, sealed with a semi-permeable membrane of silicone rubber, would be lowered down into a shaft. Gases should diffuse into the chamber and settle on a pair of gently vibrating "tuning forks", one coated with a thin layer of silver, which absorbs H2S, and the other with a layer of sodium oxide, which takes up CO2. As the fork's surfaces absorb the gases, they will get slightly heavier and their resonant pitch will fall in frequency. This is detected by an audio sensor which signals detection of the gases. The more the pitch falls, the higher the gas concentration and the better the chances of finding "black gold". Marshall
