T_he measurements of the Debye characteristic temperatures O and mean-square vibrational amplitudes tt 2 of gold in the temperature range from 300 to 1150°K are presented. All data were determined from the X-ray integrated intensities of a gold single crystal. The room temperature value O = 188 + 4°K was found to be larger than O-values reported in the literature from X-ray data. The new value of O can be compared, however, with O= 186+ 8°K calculated from the specific heat value of OD= 178 + 8°K and Poisson's ratio for gold. The temperature dependence of O is in satisfactory agreement with the volume dependence given by Griineisen's law.The Debye characteristic temperature was determined because of an apparent anomaly in the curve of thermal vibrational amplitudes versus concentration resulting from the X-ray diffraction measurements. If the room temperature value of O = 177 + 5 °K for gold reported by Alexopoulos, Boskovits, Mourikis & Roilos [Acta Cryst. (1965) 19, 349] were employed a sharp drop of the u2 versus concentration curve would result for silver-gold alloys of high gold content. However, if the value of O = 188 + 4 °K reported in this investigation together with the valueof O = 190 + 4 °K for an Ag-94"9 atom per cent Au are plotted on the above curve a smooth curve of u2 versus gold composition is obtained.

Direct Visualization of the Haemoglobin Molecules Indirect determinations of the shape and size of the haemoglobin molecules, careers of oxygen in blood, have been made by different authors~-~). I n the present work, the mole-The electron microscopic evidence t h u s greatly corroborates the very recent works of PERIJTZ et al.S).

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