10923. Kracek, F. C.   The System Sodium Oxide-Silica.   , 1930, Journal of Physical Chemistry, 34 : 1583-1598.   Printed wraps, moisture stain on top corner that impact text, usual signs of use and age, text still in very usable condition.   Paper from the Geophysical Laboratory, Carnegie Institution of Washington, No. 710.   $6.00

10922. Kracek, F. C.   The Ternary System, K2SiO3-Na2SiO3-SiO2.   , 1932, Journal of Physical Chemistry, 36 : 2529-2542, 4 figures and 2 tables.   Printed wraps, moisture stain along top that does not impact text, usual signs of use and age, text in good condition.   Paper from the Geophysical Laboratory, Carnegie Institution of Washington, No. 810.   $5.00

10920. Serratosa, J. M. and Bradley, W. F.   Determination of the Orientation of OH Bond Axes in Layer Silicates by Infrared Absorption.   American Chemical Society, 1958, Journal of Physical Chemistry, 62 : 1164-1167, 5 figures.   Reprint, good condition.    $4.00