American Journal of Science, May.—Observations on the derivation and homologies of some Articulates, by James D. Dana. It is probable that all Articulates are successional to the Rotifers. There is reason for believing further that the types of Annelids, Crustaceans, and probably that of Limuloids, had their independent Rotifer origin. The line to the lower and earlier Arachnods, that is to the Scorpions, leads up from the early Pterygotus—like Limuloids. A line of succession from Worms to Myriapods and from these to Insects, although not proved geologically, is suggested by the fact that in low-grade insects there is no proper metamorphosis, while in the higher the larval stage is lower and lower in embryonic level. The larval stage would result from an attendant retrograde embryonic change to a line parallel with the Myriapod, and beyond to the memberless condition of a worm.—Notes on apparatus for the geological laboratory, by J. E. Wolff. This paper contains instructions for making diamond saws, for sawing thin sections of rock specimens, and for the management of the arc light for purposes of projection.—An elementary expression in thermoelectrics, by Carl Barus. Two metals are thermo-electrically identical when the sign and the number of available molecular paths which the current (or better, the elementary charge) is free to take, is the same in both metals.—Gases in Kilauea, by William Libbey. Observations of bluish-green flames bursting out from the lava, made with a pocket spectroscope, revealed what was probably carbonic oxide and some hydrocarbons, shown by a band in the green, and bands in the red and blue.—Transformations of mechanical into chemical energy, III. Action of shearing stress continued, by M. Carey Lea. The most instructive experiment was that with mercuric oxide. Half a gram was taken, and after trituration the unchanged oxide was dissolved out by repeated digestions with hydrochloric acid. The reduction products were dissolved out by a few drops of aqua regia, filtered, and precipitated by hydrogen sulphide. The amount of sulphide obtained correspond to the reduction of ˙0329 gram of mercuric oxide. The amount of mechanical energy transformed into chemical was found to be 322 gram meters. Silver oxide, potassium ferricyanide, ferric ammonia, alum, silver carbonate and sulphite, and sodium chloroaurate were also successfully reduced by grinding, but not cupric chloride. A porcelain mortar was found much more efficient than one made of agate.