A Untish subject who has recently escaped from tho Sut!i furnishca the Philadelphia Fress tlio following conccriiiug tho new Merrimac : Shc s a very formidable vesscl, constructed witli much skill. Her woodwork was thcu fioisbed. On the foilowing day sho was taken aeross tho rivcr to the Trodegar Works to Iibvo her plating put on. The platea aro about ten feet long; and ten itiehes in width. ïhey are puuched eutirely through with holes for the insertion of the bolts, and will overlap ono another when in position. Like Mcrriniac No. 1, she is a formidable rain, but is somewhat smaller than the great original, whicb, ia every respect, she greatly resembles. Her roof runs up to a peak, of such a height that the sides riso at a Bbarp angle. When ironod and her maehincry put in, her guards will probably not be over one foot above tl)e water. Being much smaller, she will be far more manageable tban Álerrim.ic the first. Hor guardd were about sis fect above the water's edge. - The ram was well beaked, reaching about four feet above the deck, and extending out six or oight feet. HEB ARMAMKNT. Althougb her irmament was of oourse not yet ou board, its cliaractor was no secret. The entire publio baving access to tho vesscl, it was easy to beseen what number of guns sho was to carry, as well as their approsimate character. From other inforination, however, I can state th;it sho wiil carry one bow, ono stern, and tliree side guns. They are to bo of the samo description as those which aro mouuted at Fort üarhng, their ability to pierce our iroa armorcd vcssels baring, u tho attack upon that fortress, been exempliiied - at least to the satisfWotion of tho seocsli. The baila to be used are steel-pointed, anfl were beiug mado on the day of our departure, as wcll as previously. She is no doubt completed by this time, and ready for offensive operations, as a very large gang of workmen were cmployed upon lier. Slio is the prido of the Richmonders, who rely upon for the defonse of the city as much as upon their armies It is boastingly declared, ! and universally believed by tliem, ih.it " she will svvcep tho James lliver.1' - ■ While this is uudoubtcdly bombast, it ia ccrtain ,slio has ono fuature of fonnidableuess not possessed by Mcrriinac No. 1. Her armor platiug exteudg below the water line. OBJt OBBW. Singularly eoongfa, lier crew is to con sist of the old crew of Merrimac the first. The men were quartered on Thirtcenth stroet, a few doors from tho Examiner o!Ti:;p, in a building styled "the fciailor's llonie."