ANTIMONY. From the specific heat of antimony, as determined by Bunsen, Regnault, and others, and from the vapor density of volatile compounds, as determined by Mitscherlich, Loewig and Schweizer and others, it is certain that the atomic weight must be about 120. (Gmelin-Kraut, l. c.; and L. Meyer, l. c.) J. J. BERZELIUS: 129.03 (0 = 100 parts of pure antimony, oxidized with nitric acid, evaporated to dryness, and heated to redness, gave 124.8 antimonic antimoniate. The number of experiments and the preparation of the metal are not given. (Poggend. Ann., 8, 1826, 23.) R. SCHNEIDER: 120.3 (016); 751.9 (0 = 100). Determined by experiments on the reduction of native antimonic ter-sulphide in a current of hydrogen. The only foreign substance to be found in the mineral was silicic acid, which was determined in each case. The temperature was kept as low as possible, and the amount of sulphide volatilized, and of that undecomposed by the process, was determined. The mean composition, as ascertained by eight experiments, was 71.48 antimony-extreme difference, 0.078; and 28.52 per cent. sulphur. The atomic weight was calculated from the mean for S=200. (Poggend. Ann., 98, 1856, 293.) Schneider published a preliminary note in Poggend. Ann., 97, 1856, 483, in which, from a portion of the above-mentioned experiments, he deduced the value 120.25. H. ROSE and WEBER: 120.626 (0 = 16). Rose published this determination expressly as a confirmation of Schneider's value. Antimony ter-chloride was dissolved in water containing tartaric acid, and decomposed by hydrogen sulphide. Sulphur was removed from the filtrate by ferric sulphate, and the chlorine determined with argentic nitrate. 2.162 antimony chloride were found equivalent to 4.097 argentic chloride. [If Ag = 107.93 and Cl = 35.457, these data give Sb 120.626; or, for O 100, Sb753.92.]. Rose, adopting some other values gets 1508.67 [twice 754.34.] He also recalculates some earlier = = analyses of the ter-chloride, and the penta-chloride (Poggend. Ann., 3, 1825, 443) made by himself by the same method, which give respectively 1512.91 and 1508.6. (Poggend. Ann., 98, 1856, 455.) W. P. DEXTER: 122.336 (O = 16); 764.6 (0 = 100). Attempts were made to determine the atomic weight of antimony from its reducing action on the chloride of gold, but no constant result was obtained. Berzelius' method (vide supra) was, therefore, adopted. From the mean of ten irreproachable experiments Dexter deduces the value 1529.2; extreme difference, 3. The metal was prepared as follows: From antimony tartrate, sodium metantimonate was prepared, and antimonic acid separated out with nitric acid. The antimonic acid was reduced with carbon, and melted with another portion of antimonic acid to remove traces of sodium, etc. It was also heated in a current of hydrogen to remove traces of oxide. The investigation was carried out in Bunsen's laboratory, and with his assistance. (Poggend. Ann., 100, 1857, 563.) J. DUMAS: 122 (0 = 16). Neither the reduction of cervantite nor of the sulphide, nor the oxidation of metallic antimony gave accordant results. Dumas, therefore, resorted to the analysis of the ter-chloride with argentic nitrate. The chloride was prepared by three different methods, and was dissolved in water acidulated with tartaric acid. Seven experiments gave an average of 121.975; extreme difference, 0.69. Ag= 108; Cl35.5. (Ann. de Chim. et de Phys., (3,) 1859, 175.) F. KESSLER: 122.24 (0 = 16). In four experiments crystals of antimony ter-oxide were employed. This oxide had been sublimed in a current of pure, dry carbonic acid. A known weight of the compound was nearly oxidized in a chlorhydric acid solution by a known, slightly insufficient, weight of potassic chlorate. The remainder was titrated with a standard solution of potassic bi-chromate, and countertitrated with ferrous chloride. The mean result was Sb 122.16. In three experiments metallic antimony was employed. It was prepared by reducing the precipitate formed when ammonic hydrate is added to stibium-ammonium tartrate. The metal was oxidized in chlorhydric acid solution by potassic chlorate, (not weighed,) and reduced to antimony ter-chloride by = stannous chloride. The excess of this reagent was chloridized by mercuric chloride, calomel being separated by filtration. The experiment was continued exactly as in the cases where the oxide was taken to start with. The mean of the experiments on metallic antimony was 122.34. The mean of the seven experiments above described is 122.24; extreme difference, 0.94. K = 39.12; Cl = 107.97. Kessler also made experiments by Rose's method, but got discordant results. (Poggend. Ann., 113, 1861, 145.) B. UNGER: 119.76 (016). Determined by analysis of sodium sulph-antimonate, (Schlippe's Salt.) (Kopp's Jarresbericht, 1871, 325; Arch. der Pharm., (2,) 147, 193; 148, 1.) A single determination by a method from which great accuracy could not be expected. S= 32; Na = 23. 23. (J. P. Cooke, Jr., in Proc. Amer. Acad., 13, 6.) J. P. COOKE Jr.: 120 (016). Cooke objects to the determinations of Dexter and Dumas, on the ground that there is no sufficient evidence of the absence of higher or lower compounds of the same elements in the salts employed. = In two experiments antimony was dissolved and precipitated as sulphide, which was heated to 240° before weighing. The formation of free S was prevented, occluded tartaric acid was determined, but occluded oxy-chloride was neglected. The experiments gave each Sb 120.6 for S 32. In thirteen experiments Sb was dissolved in a minimum of nitric acid, and the solution boiled over bullets of Sb to complete saturation. The sulphide was then precipitated in an atmosphere of carbon di-oxide. The precipitate contained no free S. The oxy-chloride was driven off at 180° and determined. The tartaric acid was decomposed at 210° and determined. The errors are opposed and minute. The mean of the weighings of sulphide, dried at 180°, gave Sb 119.994 for S= 32; extreme difference, 1.01. The mean of weighings of sulphide heated to 210° gave Sb 120.295; extreme difference, 1.07. General mean Sb = 120.145. Fifteen analyses of antimonious bromide gave the Br contents at 66.6665 per cent. for Ag= 108, Br = 80, with an extreme difference of 0.195. This composition gives Sb 120. In seven experiments the iodide was analyzed. For I=127 and Ag 108, it gave a mean of 76.051 per cent. Sb, or Sb =120. It was also shown that the chloride = = = cannot be prepared free from oxy-chloride, and that its Sb and Cl contents correspond to Sb = 120. Metallic Sb was prepared by reduction of sodic antimoniate, or of oxide, with potassic cyanide, or by Liebig's method. In all cases it was fused for several hours under its own oxide. The haloid salts were purified by fractional recrystallization and distillation, in part in a current of carbon di-oxide. (Proc. Am. Acad., 13, 1877, 1.) ARSENIC. The specific heat of metallic arsenic, as determined by Regnault, and the vapor density of a number of volatile compounds, as determined by Dumas, Mitscherlich, Bunsen, and others, prove that the atomic weight of this element must be in the neighborhood of 75. (Gmelin-Kraut, l. c.; and L. Meyer, l. c.) = 16); 469.4 (0 = 100). J. J. BERZELIUS: 75.1 (O 2.203 grammes of arsenious acid, heated with sulphur in a distilling apparatus in such a manner that sulphurous acid, but no sulphur, could escape, set free 1.069 grammes sulphurous acid. If S 200.75, the value follows. (Poggend. Ann., 8, 1826, 22; and Lehrbuch, 5 ed., 3, 1205.) = J. DUMAS: 75 (0 = 16). Dumas found the vapor density of arsine 2.695. [This value multiplied by 28.94278 gives As = (sensibly) 75.] (Ann. de Chim. et de Phys., 33, 1826, 337.) J. PELOUZE: 75 (0 = 16); 468.75 (O = 100). A known weight of arsenic ter-chloride was introduced into a nitric acid solution of a known weight of perfectly pure silver, the chloride being in slight excess. The excess of chloride was then titrated with decimal silver solution.* As the mean of three experiments Pelouze found As = 937.50; extreme difference, 0.8. Ag 1349.01; Cl 443.2. The ter-chloride was repeatedly distilled to free it from excess of chlorine. It was colorless, dissolved com = = * This method, which has been frequently employed in the determination of atomic weights, will be referred to as "Pelouze's method." pletely in chlorine, and boiled between 134° and 135°. (Paris Comptes Rend., 20, 1845, 1047.) J. DUMAS: 74.94 (0 = 16). Determined by four experiments on the titration of arsenic ter-chloride with argentic nitrate, the ter-chloride being prepared in several lots. The number is the mean of the experiments; the extreme difference being 0.15. Dumas takes Ag=108; Cl=35.5. (Annal. de Chimie et de Physique, (3,) 55, 1859, 174.) F. KESSLER: 75.2 (0 = 16). In six experiments arsenious acid was titrated with potassic bichromate and counter-titrated with ferrous chloride. The number so obtained was 75.15. In twelve experiments a known weight of arsenious acid was oxidized in caustic potash solution by potassic chlorate, the arsenious acid being slightly in excess, acidified with chlorhydric acid and the excess of arsenious acid titrated with potassic bichromate and counter-titrated with ferrous chloride. The oxidizing action of the potassic bichromate was experimentally determined. The number obtained from these experiments was 75.24. Five experiments were made with acid instead of alkaline solutions of arsenious acid; they gave 75.15. The arsenious acid was colorless, transparent, volatilized without any residue, and was thoroughly dessicated. Kessler assumed K 39.12; Cl 107.97. (Poggend. Annal., = 95, 1855, 210; 113, 1861, 140.) BARIUM. The specific heat of barium compounds, especially of the chloride, as determined by Regnault and by Kopp, shows that the atomic weight of this element lies in the neighborhood of 137. (Gmelin-Kraut, l. c.) WOLLASTON and KLAPROTH. 139.2 (0 = 16); 870 (0 = 100). Klaproth found that 100 parts of carbon di-oxide were equivalent to 352.57 parts barium oxide, and that 34 parts sulphuric anhydride were equivalent to 66 parts of barium |