FmtfrlDi *. m r?f—w e an favoured b\ yestprdav's mail with a letter fromN* ^ Orleans nt Mav 1st. tsavs theOii^nrr, in which we find that animj«vrfaiit discovery bud beeti made a few days previous, in that c ity* The fdlowmg is an extract;— Four daysage *ome planter1' were diggifig, underground the* I* und a square room containing ivvtn thousand stands oi arms and fi/Wn thousand cartridges—each«Mihlt; cartnders containing a bullet.1*The negroes, it is staid* intended to rise soon us the mlt; Uv season began* and obtained possession of the city, maaa-rrrting tae pi inters and white population. The % me states the Mayor imtigmliibiM the opening of Sunday_ rhools lor the instruction of blacks, under .1 penalty of (Wc dollars for thefirM olfer.CC, and lor the sucond, drolA.