Wiedemann's Annalen der Physik und Chemie, No. I.—Radiation of gases, by F. Paschen. The experiments were conducted upon gaseous carbonic acid and steam. By using mirrors instead of lenses, and a prism of fluor spar, purer spectra and more decided maxima were obtained than those found by Angstrom. The absorption spectra of CO2 at ordinary temperatures, and of steam at 100°, correspond in general to the emission spectra at higher temperatures, except that at higher temperatures the maxima are displaced towards the less refrangible end. This displacement was found, however, to be reversed for at least one of the steam maxima. The principal maximum of CO2 was at λ 4630. The other, at 2710, nearly coincided with that of steam, at 2660. The other maxima due to steam were found at 8060 and 7160. All these maxima were very decided. A layer of CO2 7 c.m. thick showed almost complete absorption at the darkest bands. These bands did not, as sometimes supposed, broaden with increasing thicknesses of layers. A layer of air 83 c.m. thick showed them clearly. One principal band due to steam was found represented in the absorption spectrum of water, but those of water were as a rule displaced towards the red end. No absorption by oxygen and nitrogen could be discovered under similar conditions.—On the artificial colouring of crystals and amorphous bodies, by O. Lehmann. The recently discovered phenomenon of “liquid crystals,” i.e. dissolved crystals retaining their doubly-refracting properties in the state of solution, has confirmed the author's belief that the properties of crystals depend more upon those of their molecules than upon the aggregation of the latter. Hence it is probable that substances which are not isomorphous may, after all, be capable of crystallising together. This has been actually observed in the case of sal-ammoniac and copper chloride, and subsequently in a large number of substances, such as meconic, hippuric, and succinic acids when brought into contact with bodies like Hofmann's violet, phenyl blue, or methyl orange.—On galvanic deposits arranged in streaks, by U. Behn. The streaky deposit found in silver voltameetrs and similar apparatus owes its arrangement to currents within the liquid due to variations of density during electrolysis, as was proved by varying the position of the voltameter. In the case of silver nitrate, the streaks are most highly developed when the solution is dense and the current feeble. The amount of E.M.F. is without influence.—The polarisation of solid deposits between electrolytes, by P. Springmann. The counter E.M.F. generated by a current flowing through two electrolytes was determined, in cases where the two liquids gave a solid deposit upon the membrane (parchment or gypsum) separating them. With a current of 21˙4 milliamperes, solutions of lead nitrate and copper sulphate gave a polarisation of 1˙964 volts after five, and 2˙02 volts after ten minutes.