"Washington', May 2. The forraolitios nccessary to be amarad to carry out the fonvention made winter vrith Spain by Gen. Sickles, for a oommission to sit in this city for tho detennination of olaima of American citizcns agiiinst the Spaiiish GoTcrnment, growing out of the insuirection in Cuba, are benig rapidly pushed forward. TIn; timefor the meeting wiD ba fbctd at an early date. This commission will be imlike tho Mexican oommission in tlii there are no counter claims to be brought Rgaiott. this jjoverniBnt.