Twenty-five microphotometer scans from Stratoscope granulation photographs distributed across the solar disk have been analyzed statistically to yield amplitude distributions, power spectra, and related quantities. Power spectra have been calculated for twenty additional scans of the center of the disk obtained by Schwarzschild (1959). A difference in calibration procedures in part explains RMS's that are nearly twice those obtained by sChwarzschild. The range of wave numbers k1 for which power-spectra calculations yield quantitative results is limited by uncertainties in low-wave-number filtering to k1 > 0.001 km-' and by what is probably instrumental noise in the photographs to k1 < 0.008 km-'. This upper limit is further reduced to k1 < 0.004 km-' or less by instrumental corrections, using the method of Uberoi (1955b) generalized for foreshortening. These corrections account for the instrumental profile of the Stratoscope (determined from the limb of the solar disk),for focus of the photographs, and for the analyzing spot and focus of the microphotometer. The variation in the relative brightness fluctuation RMS across the solar disk (Figs. 4 and 9) is characterized by an increase from 0.14 for the central regions of the disk (out to 0 20 , to 0.20 at 0 50 and then a sharper decrease, which levels off and reverses itself at 0 70 . Ezamination of limb photographs attributes this reversal to the emerging photometric importance of a large-scale, essentially unforeshortened, pattern which does not seem to be instrumental or telluric aild may not be part of the normal photosphere granulation. Scatter in the RMS of adjacent scans can be attributed to statistical inhomogeneities in the granulation pattern. The amplitude distributions are approximately Gaussian (Fig. 3) with moderate positive skewness. The power spectra (uncorrected, Tables 3 and 4 and Figs. 2 and 5; corrected, Table 8 and Fig. 10) are characterized by a rapid decrease with increasing k,. A steepening of this falling-off toward the limb is probably due to the large-scale pattern. The variation in the brightness fluctuation RMS across the disk has been converted to the RMS of temperature fluctuations as a function of optical depth, using the Eddington-Barbier approximation (Fi . 11). The maximum of brightness RMS at 0 50 becomes a maximum in temperature RMS of 290 K at r 0.65. An inhomogeneous model solar atmosphere based on these temperature fluctuations has been constrncted (Table 9), and, using the&etical results of Ledoux, Schwarzschild, and Spiegel (1961), an associated velocity spectrum and convective transport have been roughly determined. Scans of two special regions have been analyzed: a region at the center of the disk, which is characterized by a low RMS and a flattened spectrum, and a facular region, which shows the normal spectrum and ouly a slightly higher RMS.