The Bragg-edge positions of an annealed sample correspond to those of a cast sample whilst the total cross section of an annealed sample is smaller than that of a cast sample. The total cross section may be influenced by the crystallite size and extinction. Multiple scattering will occur in the same crystal grain if the crystallite size is large. The extinction seems to increase with increasing crystallite size. Powdered Si is prepared by rushing the single crystal of Si, so that the grain size agrees with the crystallite size. Si was sieved to get grain sizes about 2.7 mum, 100 mum and 200 mum, respectively. The Bragg-edge positions among the three samples are the same. The total cross section decreases with increasing crystallite size. It is found that the total cross section depends on the crystallite size and the extinction is one factor to decrease the value of the total cross section. Bragg-edge neutron transmission is a useful tool as a nondestructive test.