SECTION V. OF BITUMENS. BITUMENOUS OILS. 1. Naptha is an oil of a brownish yellow colour, and is considered as a volatile oil, as it possesses some of the properties of those oils. Its specific gravity varies from 0.730 to 0.878. It is found in the earth. When darker coloured and less fluid, it is called petroleum. If petroleum be distilled, naptha is obtained from it. 2. Maltha, or sea-wax, is a solid substance found in a lake in Siberia, which seems to possess the character of a solid volatile oil, as it is soluble in alcohol, &c.. PROPER BITUMENS. The general properties of that class of bitumens, which Dr. Thomson calls proper bitumens, are as fol lows: 1. They are either solid or of the consistence of tar. 2. Their colour is brown or black. 3. They leave a peculiar smell, called bitumenous. 4. They melt when heated, and burn with a bright flame, giving out much smoke and a peculiar flavour. 5. They are insoluble in water or alcohol. 6. They do not combine with alkalis. 7. Acids have little action upon them. There are several kinds, which we shall briefly notice, viz. 1. Asphaltum, which is usually black, and found in great abundance in the island of Trinidad. 2. Mineral Tar, called also Barbadoes tar, from the place in which it is generally found, is of a blackish colour, and appears to be composed of petroleum: and asphaltum. E f 3. Mineral Caoutchouc, which is found in Derbyshire, England, and approaches the nature of vegetable caoutchouc. 4. Retinasphaltum, composed of resin, asphaltum, and earths, found in Derbyshire accompanying Bovey coal. 5. Pit-coal, of which there are several varieties, such as brown-coal, black-coal, glance-coal, &c.; composed of different proportions of bitumen, charcoal, &c. CONCLUSION. It was our intention to have embraced animal and vegetable chemistry; but as these subjects are principally matters of fact without affording extemporaneous experiments, and as they are of themselves extensive, we have thought it better to defer treating of them, and to refer the reader to the more voluminous works of Thomson, Murray, and other authors. THE END. MEDICAL BOOKS. ISAAC PEIRCE, NO. 12, SOUTH FOURTH STREET, PHILADELPHIA, Respectfully informs the Students of Medicine, and others, that he keeps constantly for sale, a large and general assortment of Books in the various branches of Medical Science, AMONG WHICH ARE, Accum's Chemistry, 2 vols. Accum's Analysis of Minerals. Assalina on the Plague. D. C. 5 00 1 00 Materia Medica of the United States. Armstrong's (Dr. John) Art of Preserving Health. 62. Baillie's Morbid Anatomy of the Human Body. Barton's (Dr.) Collection for an Essay towards a Bell's (John) Principles of Surgery. 1 00 1 50 2. 00 $5.00 Bell's Anatomy of the Human body. 11.00 Bell's (Charles) on the Diseases of the Urethra. 1 50 Bell's System of Opperative Surgery. 7 50 14 00 Bell's (Benjn.) System of Surgery, 4 vols. Bell on the Theory and Management of Ulcers. Cavallo's Complete Treatise on Electricity, 3 vols. 9 00 Chaptal's Elements of Chemistry. Cheselden's Anatomy of the Human Body, with 40 plates. 250 Chisholm on Malignant and Pestilential Fever. 2.00 1 50 Coxe's American Dispensatory. 4 00 Cullen's First Lines of the Practice of Physic, 2 50 & 6 00 Cullen's Treatise on Materia Medica improved by Benjamin S. Barton. $5.00 Currie's Medical Reports. 275 Essays and Observations, Physical and Literary, 3 v. 7 50 Cutbush (James) On Hydrostatics or Specific Gravity. Culpepper's English Physician, enlarged. D. C. 37 1.00 Darwin's Zoonomia, or the Laws of Orgoric Life. 6 00 Darwin's Phytologia. Denman's Introduction to the Practice of Mid wifery. Dewees' Abridgment of Baudelocque. 3 50 3.00 4 00 Fontana on Poison, &c. &c. 5 00 Fyfe's Compendium of Anatomy. Haller's Physiology, improved by Cullen. Henry's Epitome of Chemistry. S 00 2 50 Hunter's Anatomist's Vade Mecum. Innes' Description of the Human Muscles. London Dissector, or system of Dissection. Rush's Medical Inquiries and Observations, 4 vols. 10 00 Saint Pierre's Botanical Harmony Delineated. MAY BE HAD AS ABOVE, Every other Medical Work of merit in the market, and on the most reasonable terms. 75% 2.00 3 00 2.50 1:50 |