Some experiments recently made by M. Olszewsky appear to show that liquid oxygen is one of the best of refrigerants. He found that when liquefied oxygen was allowed to vaporize under the pressure of one atmosphere, a temperature as low as -181.4 deg. C. was produced. The temperature fell still further when the pressure on the liquid oxygen was reduced to nine millimeters of mercury. Though the pressure was reduced still further to four millimeters of mercury, yet the oxygen remained liquid. Liquefied nitrogen, when allowed to evaporate under a pressure of sixty millimeters of mercury, gave a temperature of -214 deg. C., only the surface of the liquid gas became opaque from incipient solidification. Under lower pressures the nitrogen solidified, and temperatures as low as -225 deg. C. were recorded by the hydrogen thermometer. The lowest temperature obtained by allowing liquefied carbonic oxide to vaporize was -220.5 deg. C. * * * * * CONVALLARIA. By OTTO A. WALL, M.D., Ph.G. Cnovallaria Majalis is a stemless perennial plant, found in both the eastern and western hemispheres, with two elliptic leaves and a one-sided raceme bearing eight or ten bell-shaped flowers. The flowers are fragrant, and perfumes called "Lily of the Valley" are among the popular odors. Both leaves and flowers have been used in medicine, but the rhizome is the part most frequently used. [Illustration: CONVALLARIA.] The fresh rhizome is a creeping, branching rhizome of a pale yellowish white color, which, on drying, darkens to a straw color, or even a brown in places. When dry it is about the thickness of a thick knitting needle, swelling to the thickness of a quill when soaked in water. It is of uniform thickness, except near the leaf-bearing ends, which are thicker marked with numerous leafscars, or bare buds covered with scales, and often having attached the tattered remains of former leaves. Fig. A shows a portion of rhizome, natural size, and Fig. B shows another piece enlarged to double linear size. The internodes are smooth, the rootlets being attached at the nodes. The rootlets are filiform, and darker in color.