Results are presented of measurements of the thermal conductivity (90-1328\ifmmode^\circ\else\textdegree\fi{}K), the electrical resistivity (300-1273\ifmmode^\circ\else\textdegree\fi{}K), and the Seebeck coefficient (350-1273\ifmmode^\circ\else\textdegree\fi{}K) for single-crystal and large-grained polycrystalline specimens of 99.99+% pure silicon. The thermal conductivity above 387\ifmmode^\circ\else\textdegree\fi{}K was measured by an absolute radial-heat-flow technique; below 350\ifmmode^\circ\else\textdegree\fi{}K, by an absolute longitudinal technique. Some intermediate thermal-conductivity measurements from 300-400\ifmmode^\circ\else\textdegree\fi{}K were made on the polycrystalline material using a comparative longitudinal-heat-flow apparatus. The estimated errors of these three thermal-conductivity methods were \ifmmode\pm\else\textpm\fi{}2%\ifmmode\pm\else\textpm\fi{}2\ifmmode^\circ\else\textdegree\fi{}K, \ifmmode\pm\else\textpm\fi{}1.2%\ifmmode\pm\else\textpm\fi{}0.1\ifmmode^\circ\else\textdegree\fi{}K, and \ifmmode\pm\else\textpm\fi{}4.0%\ifmmode\pm\else\textpm\fi{}1\ifmmode^\circ\else\textdegree\fi{}K, respectively. The estimated error for the electrical-resistivity measurements was \ifmmode\pm\else\textpm\fi{}1.4%\ifmmode\pm\else\textpm\fi{}2\ifmmode^\circ\else\textdegree\fi{}K, and for the Seebeck measurements \ifmmode\pm\else\textpm\fi{}1.6%\ifmmode\pm\else\textpm\fi{}2\ifmmode^\circ\else\textdegree\fi{}K. The thermal-conductivity values were compared with conflicting data from the literature, and they corroborate the higher-temperature results obtained by Glassbrenner and Slack. Therefore, we agree with their conclusion that the electronic contribution is reasonably close to theoretical estimates which include a large ambipolar-diffusion term. The temperature dependence of the lattice thermal resistance has been compared to various theoretical models but no approach seems to explain the data in detail. An abrupt slope change in the thermal resistivity at about 670\ifmmode^\circ\else\textdegree\fi{}K is a major cause of the difficulty.