"1. The communications from contributors must consist of a single sheet of paper, not larger than the accompanying engraving, with a simple ground-plan upon a scale of 1·1000 of the full size, with such elevations and sections only of the building, and on the same sheet, as may be necessary to elucidate the system proposed--such elevations and sections not being intended to convey more than a general idea of the building, and not entering into details of construction or of architectural decoration--to be accompanied by a short, clear-written explanation of the system recommended, on a separate sheet. Any contributor wishing to send two designs must send separate and distinct communications, each conforming to the above conditions. No communications made inconsistent with these conditions, or any plan prepared upon a different scale from that prescribed, can be received. The plans, &c., must be sent on or before the 8th of April next, addressed to the Secretaries of the Exhibition, New Palace at Westminster, London. It is suggested that the most convenient mode of preparing the plan, elevation, and section, would be to draw them upon one of the engraved copies of the plan of the ground which accompany these instructions.--2. The building is to be erected on the space marked A B C D, and must not extend beyond the boundaries of the shaded portion. The groups of trees shown on the plan must be preserved. The principal public approaches are by the roads E F and G H. The road K L will be available only for foot-passengers. There will be no objection to the formation of cross-roads between the two last, G H and K L, if the design of the building requires it.--3. The roofed portion of the building is to cover a space of 700,000 square feet, or about 65,000 square metres; and the whole building must not occupy, including open spaces, an area of more than 900,000 square feet, or about 84,000 square metres. The building generally will be of one storey only.--4. No space will be required for cattle, or for shrubs or flowers.--5. It may be assumed, so far as it affects the ground-plan, that the light will be obtained entirely from the roof, and the building will be constructed of fire-proof materials.