THE AGING OF AMMONIUM CHLORIDE SMOKES

In an extension of earlier work, studies have been made of the time variations in the particle number and size and mass concentration of 'still' ammonium chloride smokes having a wide range of initial mass concentration. Direct measurement of losses to chamber surfaces was an important feature of the experiments since it provided an additional quantity to be satified by theory and permitted a more critical evaluation of the coagulation and loss constants than was previously possible. Satisfactory agreement was found between theory and observation. The dependence of the loss constant on smoke chamber dimensions was found to be in accordance with expectation. The coagulation constant was 4.3 × 10 −8 cc. per min. for the least dense, but tended to a larger value for the more dense smokes. A revision of the constants obtained from earlier data indicated that the coagulation constant was little affected by turbulent air motion below a more or less critical value.