Dust, gas, and the evolutionary status of the radio galaxy 8C 1435+635 atz=4.25

We present the results of new rest-frame far-IR observations of the z=4.25 radio galaxy 8C 1435+635, which not only confirm that it contains an enormous quantity of dust (as first inferred from its millimeter-wave detection by Ivison in 1995), but also allow the first meaningful constraints to be placed on the mass of this dust and associated gas. The new measurements consist of (1) clear detections of submillimeter continuum emission at \ensuremath\lambda