THE ANALYST. 39 A SIMPLE ARRANGEMENT OF LENSES FOR READING THE GRADUATIONS OF CHEMICAL AND ASSAY BALANCES. BY G. T. HOLLOWAY, F.I.C. (Shown at the .Meeting, December 6 , 1905.) THE usual telescopic or portable lens arrangements are, as shown in the figure, replaced by lenses cemented ou the rising glass-front of the balance. Plano-convex lenses cemented with seccotine on the inside of the glass are preferred, but bi-convex lenses cemented at the edges in two or three places to small discs of cork, or other soft material cemented on the glass, may be used, as shown in the case of the upper lens in the accompanying figure. A 3-inch lens for the pointer reading is a convenient size, but 8 2-inch lens is sufficient for reading the beam graduations. A slight movement of the head suffices to bring any part of the beam into the field. The focal length of the lenses is of little importance, but they must not be powerful'enough to produce distortion, or thick enough to prevent the rise and fall of the balance-front on which they are fixed. There is always sufficient space for any ordinary lens, and as the lenses are fixed inside, they remain clean and require no attention or adjustment. As the lenses are not required except when the rider is being used, they are out of the way while the balance-front is 'raised. This arrangement is simple and cheap, and absolutely effective in saving &iia to the eye, and may be applied with advantage even to a rough balance.