The Rebels Propose To Take Washington--but Don't

New York, April 7. The ITcraWa digpatoh says : " It bas been ascertained that the rebel leaders are grievously disappeinted and diseorfcerted by the ohangc of programme in the disposition of tho army of the Potoinac. Thcv had early iuformation of' the preparation for the transportation of Gen. McClellan's army, aud supposing that the whole army of the Potomac was to be withdrawn from this vioinity, had arranged a programme for a bold dash aeross the Potomac above Washington, and a foray upon the capital through Maryland, Gen. Jaekson's command was to be supported by Smith and Johnston's forces. It was expeeted that the rebel sympathizers in Maryland would raise tlio standard of revolt there and the execution of the projeet by the destructiou of railroads and bridges, and the isolation of Washington. From reinforcements of Union troops, the rebel leaders reckoned without their host and were taken by surprise at finding Gen. Banks withiu supportiug distunce of Gen. Shields whcn the attempt was mado to execute tlie first part of their programme. Tho rcpuUe of Juekson and tho creation of two new departmeuts in Virginia undcr commaud oí Geu. Banks and McDowell, convinces them that no vulnerable point has been lcft unprateoted. Tho jMaryland gympathizer, who wero emboldened to insolence at tho prospect of tilia bold feat of tho rebel army, huve bccome dísheartened and are leaving by scores. Numbers havo been axrosted in their attempt to escape Soulh, and others who were known to have organista for the occasion, are eeekrng" avenues southw&rd in small partieg."