Julian M. Blair

Concerning the Cutting of Glass

Glass plates were found to be more difficult to break when an interval elapsed between marking and breaking. This was associated with a decrease in the strain. Apparatus for applying uniform force in marking glass is described; also, a device for studying breaking loads. Marked samples of glass were found to break when subjected to diminished loads for appreciable intervals. A correlation was shown between the breaking load and the load on the marker.

The Blair-Leighton equation applied to the production of the latent photographic image by hydrogen peroxide

Abstract 1. 1. Data published by Sheppard and Wightman are interpreted as supporting the Blair-Leighton equation. 2. 2. Data presented here also indicate that the rate of formation of the latent image by hydrogen peroxide follows the same equation. 3. 3. Variations of the data of Sheppard and Wightman from the horizontal portion of the theoretically computed curve are not confirmed by data from this laboratory. 4. 4. Evidence is presented that there is no direct correlation between the behavior of emulsions upon exposure to light and to hydrogen peroxide for ( a ) emulsions identical in their reaction to light differ widely in their sensitivity to hydrogen peroxide and ( b ) emulsions differing widely in their light sensitivity show little difference in their behavior with hydrogen peroxide. 5. 5. Evidence is presented which tends to show tht the process of production of the latent image by different agents is fundamentally identical.

The Effect of Concentration on the Production of the Latent Photographic Image by Hydrogen Peroxide

Much of the density previously reported as produced by short immersions of photographic plates in aqueous solutions of hydrogen peroxide was found to have been produced during the washing interval between exposure and development. Data are presented concerning the production of the latent image by various concentrations of hydrogen peroxide. Analysis of this data suggests that, initially, the net reaction is of the second order. An optimum concentration for the production of maximum density was indicated.