By means of this machine it is possible to obtain very valuable information concerning the effect of age upon a paint as influencing 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 qualification of a paint may easily be seen through the checking of oil paintings, which, as Ostwalt has pointed out, is due to the unequal coefficients of expansion between the ground and the paint. This is particularly noticeable in the alligatoring of many enamels which contain large percentages of zinc. Curves have been prepared having pressure as an abscissa and elasticity as ordinate. These curves show remarkable differences in different pigments. For instance, in the case of white lead, the curve takes a steep upward trend when it apparently reaches a maximum, the curve then flattening out and finally taking another steep upward trend just before breaking. This may be construed as follows: That under low pressures the white lead film is perfectly elastic, when a maximum is obtained, beyond which elasticity does not extend. This point is the maximum point of the upward trend. From here on pressure may be applied without any increase in stretch, this being represented by the flat part of the curve, while the steep upward trend just before breaking shows where the paint begins to tear, finally culminating in breaking. In the case of asbestine, however, the curve is more of a straight line up to the breaking point, which would go to prove that elasticity is proportionate to pressure in the case of this pigment. =Moisture Absorption.= The structure of certain pigments is such that when they are ground in linseed oil and painted out, films are produced which are very water-resistant. This action is possibly due to the filling of the voids in the oil, thus making a compact and water-resistant film. Pigments which are coarse and which present an angular crystalline structure, often produce films which contain a relatively large number of voids and are less waterproof. Certain pigments are chemically active and tend to produce, when ground in oil, metallic soaps which act for a time more or less as varnish gums, in keeping out moisture. Later on, however, such films are apt to break down and admit moisture in quantity. The tests herein described were designed by the author to determine the water-excluding value of a number of typical pigments when ground in linseed oil and painted out into films. Unfortunately, no method has been devised by which films of the same gauge could be prepared. The variations in the thickness of the films used in these experiments, however, are not very great. [Illustration: Apparatus for Determining Excluding Properties of Paint Films]