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PAINT TECHNOLOGY AND TESTS 



It consists of a three-necked Wolff bottle having provision 

 at one of its necks for exhausting the air from the bottle. The 

 reverse neck is provided with a gauged glass tube dipping into 

 a porcelain crucible containing mercury, thus acting as a manom- 

 eter. The middle neck is fitted to accommodate two ground 

 glass plates. Both these plates are provided with a central 

 orifice one millimeter in diameter. Between the plates is placed 

 a small section of paint film. The plates may be pressed together 

 or clamped together and placed over the middle neck of the 

 bottle, a close contact being made with Canada balsam. As 

 the air is exhausted from the bottle, the mercury in the tube 

 will rise and continue in its ascent until the film, which is 

 exposed to atmospheric pressure, has offered it maximum resist- 

 ance, which is shown by the breaking point. This point is 

 observed on the manometer and the result expressed in centi- 

 meters of mercury. 



Table of Film Testing Results. By means of the Perry film- 

 testing apparatus, described in the above, interesting results have 

 been obtained, which are embodied in the following table: 



COMPARATIVE STRENGTHS OF FILMS AS OBTAINED BY THE BREAKING 



MACHINE 



By means of this machine it is possible to obtain very valuable 

 information concerning the effect of age upon a paint as influ- 

 encing its strength and elasticity. These are two vital qualities 

 in a paint, as it is through its strength that a paint resists abrasion 

 cracking, peeling, and blistering. That elasticity is a vital quali- 



