THE EDINBURGH NEW PHILOSOPHICAL JOURNAL, EXHIBITING A VIEW OF THE PROGRESSIVE DISCOVERIES AND IMPROVEMENTS IN THE SCIENCES AND THE ARTS. CONDUCTED BY ROBERT JAMESON, REGIUS PROFESSOR OF NATURAL HISTORY, LECTURER ON MINERALOGY, AND KEEPER OF Fellow of the Royal Societies of London and Edinburgh; Honorary Member of the Royal Irish Academy; of the OCTOBER 1839....APRIL 1840. VOL. XXVIII. TO BE CONTINUED QUARTERLY. EDINBURGH: ADAM & CHARLES BLACK, EDINBURGH; LONGMAN, ORME, BROWN, GREEN & LONGMANS, LONDON. 1840. CONTENTS. ART. I. Researches on the Electrical Currents in Metallife- rous Veins, made in the mine of "Himmelfahrt," near Freyberg. By Professor F. REICH of Frey- V. On the Transverse Valleys or Openings in Chains of Mountains, which afford a Passage to Rivers. VI. On Rivers which break through Mountain-Chains. By the late Professor HOFFMAN of Berlin, VII. Abstract of a Paper read to the Society of Arts, by Sir JOHN ROBISON, entitled, "A Narrative of Experiments and Suggestions, by the late Mr VIII. On the Habits of Testaceous Mollusca, belonging to the Genera Achatina and Phasianella. LOGAN, Esq., Surgeon, R. N. Communicated by IX. Zoological Instructions of the Royal Academy of Sciences, Paris, for the Scientific Expedition re- XI. Meteorological Observations made at the Imperial Academy of Sciences of St Petersburg, from 1822 to 1835, and calculated by M. T. Kupffer, XIII. On the Supposed Existence of Fluoric Acid, as an Ingredient in certain Animal Matters. By G. Ò. XIV. Sketch of Animal Life in Nova Zembla (Novaïa Zemlia). By M. K. E. VON BAER, XVIII. Report on the Manufacture of Tea, and on the Ex- tent and Produce of the Tea-Plantations in Assam. By C. A. BRUCE, Esq. Superintendent of Tea- Culture. With a Map of the Tea Districts, XIX. On the Calcareous and Siliceous Microscopic Ani- mals which form the Chief Component Parts of XXIII. Description of a Polyphotal Lamp, and Reflector of Single Curvature, employed in Steam-vessels, Canal-boats, &c. By JOIN SCOTT RUSSELL, A. M., |