 This result of Ramsey’s improved on earlier joint work of Paul Bernays and Moses Schönfinkel (1928) and solves the prospective Spectrum Problem (Scholz 1952), for sentences of the above form, now referred to as the Bernays-Schönfinkel-Ramsey Class. That is, for such sentences it enables us to determine the class of cardinalities of structures in which that sentence can be satisfied. As a corollary it gives that one can effectively decide if a sentence in this class is satisfiable in some structure. However it seems clear from the accompanying discussion that Ramsey was aware that there was also a direct and simple proof of this fact.