We enter the gallery by the spiral staircase in the Central Transept Gallery on the garden side of the building, and shall find that division devoted to the minerals, which we will explore first, at the left-hand extremity of the gallery. The vegetable division is naturally the largest, and occupies all the central cases and some portion of the right hand or northern extremity, where the third and last--the animal division--is situated. A plan detailing plainly this arrangement will be found suspended against the first case on the left as we enter. The first cases of the mineral division, which are those in front of the gallery on the left-hand, are devoted to what are commonly termed the _non-metallic_ elements and their most important compounds, that is to say, those compounds in which the non-metallic element is the one technically important, arranged in the order in which they are generally treated in works on Chemistry. It may be necessary here to observe, that in order to avoid needless repetition in the classification of the chemical compounds, this plan has been adopted throughout. Thus, for instance, Bleaching Powder, which might be arranged under the heads of both its constituents, Chlorine and Lime, as it is used only on account of the Chlorine, is classified under that element. In these cases we find varieties of Carbon, Products of the Distillation of Coal, Peat, &c. (Naphtha, Ammoniacal Salts, Paraffin, Dyes, &c.), and a beautiful series illustrating the manufacture of Sulphur. Succeeding these are shown the varieties of Silica, under which head a rich case of English Agates from the Sussex coasts must be particularly noticed. The Silicates embrace the different manufactures of glass, amongst which are some beautiful artificial gems. Etching upon glass is also illustrated here. We now come to the Alkaline Metals,--Potassium, Sodium, and their salts. The next are the minerals of the Alkaline earths, Barium, Strontium, Calcium (Lime), and Magnesium, and their sundry preparations. The cements come under this division. The next cases are devoted to Aluminous products, and in this class will be found complete illustrations of one of the most important and interesting of British manufactures--the Ceramic. The series commences with a collection of the clays from different formations, and the process by which the Devon, Dorset, and Cornish clays, which are those used in earthenware and porcelain manufactures, are fashioned, decorated, and finished, is shown together with the materials used for glazes. The preparations of Alum by different processes, Emery, &c. are also in this division.