Froin a lottur received yealerday from Col. O. B Willcox, dated Riclirnond, April 2d, 18G2, we make the ibllowing extract : - Vree Press, April 13th. " I havo been hero ever since the last of li'ebruary, witli no moro gpparant probability oi' uxohange than ever, and without even tho consolation of hearing from home. I can onlv say that I am well and cntiruly in the dsrk as to the causo of lnnger dotention. It is said that our government has broten o ft nogotiations. Wo are confined, as usual, in large nurabers in warehonses, without egress to even a yard for air and (.'xorciso. All the Columbia party are hcre."