“In order to test the truth of the different hypotheses made concerning this subject, A. Schulatschenko, seeing the impossibility of separating, from a mixture of silicates, each special combination thereof, repeated Fuch’s experiment, by separating the silica from 100 parts of pure soluble silicate of potassa, and, after mixing it with fifty parts of lime, and placing the mass under water, when it hardened rapidly. A similar mixture was submitted to a very high temperature, and in this case, also, a cement was made. As a third experiment, a similar mixture was heated till it was fused; after having been cooled and pulverized, the fused mass did not harden any more under water. Hence it follows that hardening does take place in cement made by the wet as well as dry process, and that the so-called over-burned cement is inactive, in consequence of its particles having suffered a physical change.” [Illustration: IRON STORE-FRONTS, No. V. BY WM. J. FRYER, JR., WITH MESSRS. J. J. JACKSON & BROS., NEW YORK.] NATIVE COLORED MARBLES. In the preceding number we have spoken in general terms of this beautiful acquisition to our art materials, and indeed we feel that we cannot esteem this new American discovery too highly; for even in Europe such stone is extremely scarce at the present day, and it is fortunate that the location in which the quarries exist is open to the Old World to freely supply the wants of its artists, as well as our own. The beautiful Lake Champlain affords excellent commercial facilities, the Chambly Canal and Sorel River improvements opening a free navigation both with the great chain of lakes, and the Atlantic Ocean. The Champlain Canal connecting it with the Erie Canal and Hudson River, giving it uninterrupted communication with New York State and its Empire City, from the latter end of March to the middle of December. The quarry is situated in a great lode projecting up in the bosom or bay of Lake Champlain, forming an island of several acres outcropping on each shore, and giving evidence that the deposit extends and really forms, at this point, the bed of the lake, its supply being thought to be inexhaustible. The marble occurs in beds and strata varying in thickness from one to six feet, and will split across the bed or grain; blocks of any required size being readily obtained. Its closeness of texture and hardness render it susceptible of a very high polish, and it will resist in a remarkable degree all atmospheric changes. It is hard to deface with acids or scratches, and this one fact should attach to it much additional value. Its variegation in color, as shown by the specimens taken from its outcroppings, give promise of a much richer development as the bed of the quarry is approached; and must equal in beauty and durability the highly prized oriental marble of ancient and modern times.