  The production of hard di-jet events in photoproduction at HERA is dominated
by resolved photon processes in which a parton in the photon with momentum
fraction x_gamma is scattered from a parton in the proton. These processes are
sensitive to the quark and gluon content of the photon. The differential di-jet
cross-section dsigma/dlog(x_gamma) is presented here, measured in tagged
photoproduction at HERA using data taken with the H1 detector, corresponding to
an integrated luminosity of 7.2 pb^(-1). Using a restricted data sample at high
transverse jet energy, E_(T,jet)>6 GeV, the effective parton density
f_gamma,eff(x_gamma) = [q(x_gamma) + bar(q)(x_gamma) +9/4g(x_gamma)] in the
photon in leading order QCD is measured down to x_gamma=0.05 from which the
gluon density in the photon is derived.
