_Photo-Micrography._--H. van Heurick. Eng. Ed. Re-edited and augmented by the author from the 4th French edition and translated by Wynne E. Baxter. With Illus. London: Crosby, Lockwood & Son. _Photography._ _Deutsches Photographen Kalender._--K. Schwier. Taschenbuch und Almanach für 1895. 14. Jahr Weimar. _Physics._ _Manual of Physico-Chemical Measurements._--W. Ostwald. Translated by James Walker. London and New York: Macmillan. _A Laboratory Manual of Physics and Applied Electricity._--E. L. Nichols. 2 vols. London and New York: Macmillan. _Anfangsgründe der Physik mit Einschluss der Chemie und Mathematischen Geographie._--K. Koppe. 20. Aufl. Ausgabe B in 2 Lehrgängen. Für höhere Lehranstalten nach den preuss. Lehrplänen von 1892. Bearbeitet von A. Husmann. II. Th.: Hauptlehrgang. Essen: G. D. Baedeker. _Elementi di Fisica ad Uso delle Scuole secondarie._--F. Cintolesi. Livorno. _Thermo Dynamics treated with Elementary Mathematics._--J. Parlseo. London: S. Low & Co. THE MOST RECENT WORK. _A Seidlitz Powder._--A. Gunn made an examination of some powders and found the blue powder to consist of magnesium sulphate and sodium bicarbonate. The white powder consisted of tartaric acid. Evidently there had been a mistake or else it was a bold attempt to cope with the cutting system and its cheap prices. One wonders that the makers should expect the unusual effect of trying to dissolve the contents of the blue paper to pass unnoticed.--_Pharm. Jour. Trans._, 1894, 534. _Ointment of Mercuric Nitrate._--C. H. La Wall (_Amer. Jour. Pharm., 1894, 525_). The following fats have been suggested as a substitute for the lard oil: Neatsfoot oil, lard, butter, peanut oil, almond oil, caster oil, palm oil, bear’s oil, ox marrow, beef suet, stearic acid, petrolatum, and almost all of the other fats from the animal and the vegetable kingdoms, and even one from the mineral kingdom, appear to have been experimented with in the vain hope of finding some fat or oil which would make a good and durable ointment. Several writers have taken another course and have tried to preserve the products obtained from former processes. One advises keeping the ointment in a jar and covering it with a layer of glycerin to prevent oxidation; others have tried the addition of camphor; still others have given their attention to the mercurial portion of the ointment, and suggest making the nitrate from the oxide of mercury instead of making it from the metal. Some have even been skeptical as to the reliability of any process, but those who have approximated the truth more nearly are they who advise careful manipulation, especially as regards temperature.