"2. The advisability of constructing it as far as possible in such a form as to be available, with the least sacrifice of labour and material, for other purposes, as soon as its original one shall have been fulfilled, thus insuring a minimum ultimate cost.
"3. Extreme simplicity, demanded by the short time in which the work must be completed.
"For the arrangements of the plan we rely for effect on honesty of construction, vastness of dimension, and fitness of each part to its end.
"The principal points of excellence we have endeavoured to attain are—
"1. Economy of construction.
"2. Facilities for the reception, classification, and display of goods.
"3. Facilities for the circulation of visitors.
"4. Arrangement for grand points of view.
"5. Centralisation of supervision.
"6. Some striking feature to exemplify the present state of the science of construction in this country.