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The chemical news
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The chemical news
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Band 1.1860
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- Titelblatt Titelblatt I
- Sonstiges Advertisement III
- Ausgabe No. 1. - December 10, 1859 1
- Ausgabe No. 2. - December 17, 1859 13
- Ausgabe No. 3. - December 24, 1859 25
- Ausgabe No. 4. - December 31, 1859 37
- Ausgabe No. 5. - January 7, 1860 49
- Ausgabe No. 6. - January 14, 1860 61
- Ausgabe No. 7. - January 21, 1860 73
- Ausgabe No. 8. - January 28, 1860 85
- Ausgabe No. 9. - February 4, 1860 97
- Ausgabe No. 10. - February 11, 1860 109
- Ausgabe No. 11. - February 18, 1860 121
- Ausgabe No. 12. - February 25, 1860 133
- Ausgabe No. 13. - March 3, 1860 145
- Ausgabe No. 14. - March 10, 1860 157
- Ausgabe No. 15. - March 17, 1860 169
- Ausgabe No. 16. - March 24, 1860 181
- Ausgabe No. 17. - March 31, 1860 193
- Ausgabe No. 18. - April 7, 1860 205
- Ausgabe No. 19. - April 14, 1860 217
- Ausgabe No. 20. - April 21, 1860 229
- Ausgabe No. 21. - April 28, 1860 241
- Ausgabe No. 22. - May 5, 1860 253
- Ausgabe No. 23. - May 12, 1860 265
- Ausgabe No. 24. - May 19, 1860 277
- Ausgabe No. 25. - May 26, 1860 289
- Ausgabe No. 26. - June 2, 1860 301
- Register Index 313
- Beilage No. 1. December 10, 1859 I
- Beilage No. 2. December 17, 1859 IX
- Beilage No. 3. December 24, 1859 I
- Beilage No. 4. December 31, 1859 I
- Beilage No. 5. January 7, 1860 I
- Beilage No. 6. January 14, 1860 I
- Beilage No. 7. January 21, 1860 V
- Beilage No. 8. January 28, 1860 I
- Beilage No. 9. February 4, 1860 I
- Beilage No. 10. February 11, 1860 I
- Beilage No. 11. February 18, 1860 I
- Beilage No. 12. February 25, 1860 I
- Beilage No. 13. March 3, 1860 I
- Beilage No. 14. March 10, 1860 I
- Beilage No. 15. March 17, 1860 I
- Beilage No. 16. March 24, 1860 I
- Beilage No. 17. March 31, 1860 I
- Beilage No. 18. April 7, 1860 I
- Beilage No. 19. April 14, 1860 I
- Beilage No. 20. April 21, 1860 I
- Beilage No. 21. April 28, 1860 I
- Beilage No. 22. May 5, 1860 I
- Beilage No. 23. May 12, 1860 I
- Beilage No. 24. May 19, 1860 I
- Beilage No. 25. May 26, 1860 I
- Beilage No. 26. June 2, 1860 I
- Beilage No. 27. June 9, 1860 I
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THE CHEMICAL NEWS. Vol. I. No. 19.— April 14, i860. SCIENTIFIC AND ANALYTICAL CHEMISTRY. Remarks upon the various Methods usually adopted for the Sejiaration of the Alkalies from the Bases with which they are generally associated in Soils, Minerals, fyc. by Frederick Field. ( Continued from p. 194.) In continuing tlie recapitulation of the various processes usually adopted for the estimation of the alkalies in minerals, &c. it will also be useful to point out one or two methods of great excellence which do hot appear to he so generally employed as their merits would lead us to expect. The action of caustic baryta has already been discussed, and the disadvantages attending its use are not lessened by the employment of the nitrate, and are even augmented by that of the carbonate. Dr. Law rence Smith, in an investigation upon this subject, first published in Silliman’s American Journal, and reprinted 111 the Chemical Gazette, has done much in facilitating the fusion of the various silicates containing alkalies, and shown that by adopting certain methods the difficulties attendant upon this class of investigation can be exceed ingly lightened, and the decomposition of the alkaline silicates very greatly facilitated. As the processes he adopts are now generally known, it will be merely ne cessary to consider their leading features and character istics. Dr. Smith first tried the fusion of the mineral under examination with carbonate of lime and fluor spar. Car bonate of lime per se acts with considerable energy upon the silicates, as it parts with its carbonic acid much more readily than the carbonate of baryta, the only obstacle to its use being the employment of a very intense tempera ture. Mixed with fluoride of calcium, which merely acts as a flux, the mineral and the lime are brought into intimate contact, and the difficulty is, to a great extent, removed. The substance to be examined, finely pulverised, is mixed with from four to five parts of pure precipitated carbonate of lime and its own weight of fluor spar, and introduced into a platinum crucible capable of holding three times the bulk of the mixed powder. It is then exposed, with the usual precautions, to a bright heat for three quarters of an hour. By this means Dr. Smith found that the most refractory silicates were entirely decomposed. After cooling, the contents of the crucible are digested with one part of hydrochloric acid and two of water, until dissolved, and carefully evaporated to dryness, an operation far easier than after the soda fusion, as the evaporation proceeds more quietly and without decrepitation. A little hydro chloric acid is added to the dry mass, and subsequently water, when heat is applied, and the liquid boiled for a few minutes. A slight excess of concentrated solution of carbonate of ammonia is introduced, and the precipi- ate, which is allowed to subside, is filtered oil. The so lution contains chlorides of ammonium, magnesium, and a little chloride of calcium, and is then partially evapo rated on a sand bath. In order to avert the great inconvenience which is al ways experienced in the evaporation of the solution of chloride of ammonium, Dr. Smith takes advantage of a fact described by himself some short time previously, viz. the decomposing effect produced by heating sal-am moniac with nitric acid. About three parts of nitric acid are added to every one of sal-ammoniac present, the so lution warmed gently, and below the temperature of boiling water decomposition, accompanied with consider able evolution of gas, takes place with great rapidity. By this means much trouble is avoided, and the evapo ration proceeds quickly and rapidly; when dried, the re sidue is dissolved in a little water, lime water is added, the liquid is boiled and filtered, the filtrate treated with carbonate of ammonia to separate the lime, and again evaporated to dryness. Dilute sulphuric acid is now added, the nitric and hydrochloric acid expelled by heat, and the alkalies left in the state of sulphates. For the conversion of the sulphates into the chlorides, Dr. Smith prefers the acetate of lead to chloride of barium; this reagent is added in slight excess, in order to precipitate the whole of the sulphuric acid; the filtrate, after warm ing, is treated with sulphuretted hydrogen, the sulphide of lead removed by filtration, excess of hydrochloric acid added to the acetates of the alkalies, and the liquid eva- orated to dryness. This process, although excellent, as since been improved by the same chemist. Dr. Smith foimd that silicates could be fused still more easily by mixing them, in a finely divided condition, with rather more than O'5 their weight of chloride of ammonium and 5 to 6 of carbonate of lime. After forty minutes strong heat in a platinum crucible the mineral is entirely decomposed. “ There is no silicate,” observes Dr. Smith, “ which, after having undergone this process, is not easily dissolved by hydrochloric acid.” But perhaps the most important point in this method is the facility with which the alkalies can bo at once se parated from the other bases without subjecting the solu tion to numerous processes before these bodies can be obtained in a state for estimation. After the mineral or other product under examination is perfectly decomposed by fusion with the required proportions of carbonate of lime and chloride of ammonium, the mass is heated with water until thoroughly disintegrated, when it is thrown upon a filter and thoroughly washed. The filtrate con tains merely the chlorides of the alkalies, a little chloride of calcium, and caustic lime. A small quantity of car bonate of ammonia is added to precipitate the two latter substances, the carbonate of lime separated by filtration, tho filtrate evaporated and gently ignited; the alkalies remain ns chlorides. Few processes in chemistry can be simpler than this. The potash and soda are both brought into a soluble con dition, and are easily and satisfactorily removed from tho other bases. As far as my own experience extends, Smith's method
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