SULPHUR 367 Gravimetric determination 369 Volumetric determination 370 SULPHATES 377 SELENIUM 379 TELLURIUM 379 CHAPTER XVII. ARSENIC, PHOSPHORUS, NITROGEN. ARSENIC 381 Gravimetric determination 383 Volumetric method, "iodine" 384 " " "uranic acetate" 389 PHOSPHORUS 394 Gravimetric determination 396 Volumetric determination 397 NITROGEN AND NITRATES 400 CHAPTER XVIII. SILICON, CARBON, BORON. SILICON AND SILICATES 405 CARBON AND CARBONATES 414 COALS 418 SHALES 420 CARBONATES 424 BORON AND BORATES 429 APPENDIX A. Table of atomic weights and other constants 433 Table for converting degrees of the centigrade thermometer into degrees of Fahrenheit's scale 435 Tables showing strengths of aqueous solutions of nitric and hydrochloric acids, of ammonia and of sulphuric acid 436 APPENDIX B. Estimation of small quantities of gold 440 Practical notes on the iodide process of copper assaying 441 Method of separating cobalt and nickel 442 APPENDIX C. A lecture on the theory of sampling 444 INDEX 450 A TEXT-BOOK OF ASSAYING. CHAPTER I. INTRODUCTORY.