X. On the detection of organic and other nitrogenized matter existing in the atmosphere

In this communication the author describes a method which he has devised, and which he names “distillation by cold,” by which lie believes the detection and determination of ammonia and other organic impurities existing in the atmosphere will be greatly facilitated. A glass funnel (usually of 8 or 9 inches) is drawn to a point and closed. It is supported in an ordinary stand, and filled with ice. Condensation of the watery vapour of the atmosphere then takes place; the dew collects into drops, which trickle down the outside of the funnel, and at last fall from the point, under which a small receiver is placed to catch them. The total quantity of liquid collected in a given time is measured, and the quantity of ammonia determined by Nessler’s test.