Light scattering and absorption by spherical particles is extended to aggregates of spheres with arbitrary shape and size. We applied the theory of G6rardy and Ausloos [Phys. Rev. B 25, 4204-4229 (1082)] to compute the total extinction loss spectra of several aggregates of nanometer-sized silver spheres from the near IR to the near UV. Silver was best suited to provide quantitative comparison with experiments concerning the scattering and absorption in the visible spectral region. Additional resonant extinction was obtained besides the resonant extinction of the single silver sphere. The spectra were discussed in detail to give general results that are independent of the particle material.