=Starting of Tests.= On account of the lateness of the season, it was found necessary to do the painting of the tests within a building, so that each formula might be subjected to fair and equal conditions of application, thus excluding the blowing of dust or rain upon the painted surfaces, which would have taken place had the panels been painted upon the fence. The painting of the panels began in January, 1908, the temperature within the buildings in which the work was done averaging 50 degrees Fahrenheit throughout the work. It was decided to test each formula in three colors, in duplicate, and on each grade of wood, exposing the duplicates on either side of the fence. Thus for one paint formula there were required 18 panels, or 6 painted in each color and on 3 grades of wood. =Paints for Tests.= The mixed paints received for the tests were in quart cans, having been especially prepared from the formulas submitted to manufacturers by the technical committee in charge of the work. They were properly labeled with their number and color, in each case. The formulas decided upon for the test are described later. The various white leads and other single pigment paints which were used were received in kegs weighing 12-1/2 pounds each, having been bought in the open market and then given a formula number. The formulas of the paints designed for both the Atlantic City and Pittsburg tests, as well as the numbers of the panels upon which the paints were applied, are shown on pages 131-133-145. The analysis of one of the combination paints applied is herewith given, to show the correct method of stating the composition of a paint. FORMULA NO. 20, ATLANTIC CITY TEST FENCE Percentage Composition ===================+=======+=======+=======+======= |Pigment|Vehicle| Total | -------------------+-------+-------+-------+------- Corroded white lead| 67.01 | -- | 42.84 | Zinc oxide | 19.89 | -- | 12.71 | Asbestine | 3.86 | -- | 2.47 | Calcium carbonate | 9.24 | -- | 5.91 | Raw oil | -- | 94.30 | 34.02 | Japan drier | -- | 3.89 | 1.40 | Turpentine | -- | 1.81 | 0.65 | -------------------+-------+-------+-------+------- |100.00 |100.00 |100.00 | ===================+=======+=======+=======+======= =Brushes.= Heavy 7-O round bristle brushes were used for the priming coat so that the paint might be well worked into the wood, while for the second and third coats three-inch chisel edge brushes were used. These brushes were, of course, washed several times with turpentine after painting each panel, so that pigments from one paint could not be carried over into a paint containing other pigments. [Illustration: Cypress Panels]