1. The public exhibition of a collection of specimens large enough to illustrate all the most important truths of Natural History, but not so extensive as to weary and confuse ordinary visitors. 2. The accessibility of this collection to the public. 3. The conservation of all specimens not necessary for the purpose defined in Paragraph 1 in a place apart. 4. The accessibility of all objects contained in the museum to the curator and to scientific students, without interference with the public or by the public. 5. Thorough exclusion of dust and dirt from the specimens. 6. A provision of space for workrooms, and, if need be, lecture-rooms. PRINCIPLE. A big hall (350 x 40 x 30) with narrower halls on either side, lighted from the top. The central hall for the public, the others for the curators, etc. The walls, of arches upon piers about 15 feet high, bearing on girders a gallery 5 feet wide in the public room, and 3 feet 6 inches in the curators'. The cases should be larger below, 5 feet deep, and smaller above, 2 feet deep, with glass fronts to the public, and doors on the curators' side. For very large specimens--e.g. a whale--the case could expand into the curators' part without encroaching on the public part, so as to keep the line of windows regular. Specimens of the Vertebrata, illustrations of Physical Geography and Stratigraphical Geology, should be placed below. The Invertebrata, Botanical and Mineralogical specimens in the galleries. The partition to be continued above the galleries to the roof, thus excluding all the dust raised by the public. Space for students should be provided in the curators' rooms. Storage should be AMPLE. A museum of this size gives twice as much area for exhibition purposes as that offered by ALL the cases in the present museum. Athenaeum Club, December 8, 1872. Dear Sir, I regret that your letter has but just come into my hands, so that my reply cannot be in time for your meeting, which, I understand you to say, was to be held yesterday. I have no hesitation whatever in expressing the opinion that, except in the case of large and wealthy towns (and even in their case primarily), a Local Museum should be exactly what its name implies, namely "Local"--illustrating local Geology, local Botany, local Zoology, and local Archaeology.