The starches have been classified by Dr. Muter, according to the appearance they give under the microscope, into five groups: _Class I_.--Hilum and concentric rings visible. All the granules, oval or ovate. Tous-le-mois, potato, arrowroot, etc. _Class II_.--The concentric rings are all but invisible, the hilum is stellate. Maize, pea, bean, etc. _Class III_.--The concentric rings are all but invisible, also the hilum in the majority of granules. Wheat, barley, rye, chestnut, etc. _Class IV_.--All the granules truncated at one end. Sago, tapioca, etc. _Class V_.--All the granules angular in form. Rice, tacca, arrowroot, oats, etc. The principal starches used for finishing cotton fabrics are potato (farina), wheat, Indian corn (maize), rice, tapioca, arrowroot, sago; the last three not so often as those previously named. [Illustration: POTATO STARCH.] [Illustration: ARROWROOT STARCH.] [Illustration: WHEAT STARCH] [Illustration: RICE STARCH] [Illustration: SAGO STARCH] [Illustration: INDIAN CORN STARCH] [Illustration: TAPIOCA STARCH] * * * * * MARBLE AND MOSAIC. [Footnote: A paper recently read before the Architectural Association, London.--_From the Architect_.] By T.R. SPENCE. I do not propose to enter into any historical details as to the first and subsequent application of mosaics. In a general sense we understand mosaic as a combination of various more or less imperishable materials--fixed together by cement or other adhesive substances--and laid over walls, floors, etc., with a view to permanent decorative effect. The substance of the tesseræ is of many kinds, namely, glass, cheap and precious marbles, hard stone, and burnt clay, these mentioned being mainly in use for architectural purposes. For decorative schemes we collect as many gradations of color as are obtainable in such durable materials in their natural or manufactured state, and thus form a color palette which we regard in the same sense as a painter would his pigments.