Test No. 1 (corroded white lead and asbestine film) allowed the passage of 0.002 gm. ammonium chloride. Test No. 2 (corroded white lead and zinc oxide film) allowed the passage of 0.0003 gm. ammonium chloride. Tests were also made with dilute solutions of other salts such as ferric chloride, having a dilute solution of potassium sulpho-cyanide on the reverse side of the apparatus. In the latter case the formation of a pink color, characteristic upon the mingling of these solutions, was obtained in a few hours. =Film-Testing Machine.= A film-testing apparatus, termed a "filmometer" by its originator, Mr. R. S. Perry, was constructed, with the following features: A graduated upright tube is fixed by means of sealing wax to two metallic plates which carry an evenly bored hole, exactly under the hole in the upright tube. This hole measures exactly one square centimeter in area, and is circular. The upright tube is graduated into lineal centimeters and is called the pressure tube. [Illustration: Gardner Accelerated Test Box] [Illustration: Perry Film Testing Machine] Attached to the lower end of this pressure tube, close to the metallic plates which serve as carriers for the paint film to be tested, is a side-neck, which is inclined at an angle of 45 degrees to the pressure tube, and serves the purpose of introducing the mercury, as will be described later. Immediately under the openings in the metallic plates which carry the film are arranged two pieces of iron inclined at a 90-degree angle, so arranged that when the pressure of mercury is applied and causes rupture of the film, the falling mercury shall be caught between these two insulated plates and cause contact. These two plates are connected up by wire with a pair of magnets, thence to an electric bell, and from there to storage batteries which supply the current. A film of paint is tested in the following manner: A piece of film one inch square is cut out and placed between the two metallic plates which hold the film immediately under the pressure tube. Mercury is run in from a burette through the side-neck and applies pressure upon the film by gravity. As the mercury is run in it rises of course in the tubes until this pressure becomes so great as to finally break the film. At this point the mercury will run out, and, falling upon the two insulated iron plates immediately below, will cause contact and close the circuit which rings an electric bell, which is a signal for the operator to shut off the inflow of mercury through the side-neck from the burette.