摘要 |
In a method for remote quantitative monitoring of a selected gas in a gaseous environment by passing through the environment radiation of a wavelength absorbable by the selected gas, an improvement comprises taking a sample of a part of the gaseous environment through which the collected radiation does not pass, and causing the sample to be introduced into a position through which the collected radiation does pass, thereby to get absorption of the radiation according to the quantity of the selected gas in the sample. |