102 



CHEMISTRY. (NEW SUBSTANCES.) 



virtue of the peculiar method by which it is 

 obtained a technical " impurity," which gives it 

 its special value. This " impurity " is sulfur 

 trioxid, the presence of which is manifested by 

 the burning properties of the gas. Clayton gas 

 is produced by the combustion of sulfur in a 

 current of air during which the temperature rises 

 sufficiently high to lead to the formation of some 

 amount of sulfur trioxid. The gas is used 

 mixed with air in the proportion of 10 to 15 per 

 cent. It is said that less than 5 per cent, of the 

 Clayton gas will destroy rats and other vermin, 

 while at least 15 per cent, of pure sulfur dioxid 

 is required for the destruction of vermin life. 

 Yet Clayton gas has no appreciable action on 

 colored materials, foodstuffs, paints, or dry met- 

 als except in a moist atmosphere. Its fire-extin- 

 guishing qualities are also remarkable; a mix- 

 ture containing 8 per cent, of it rapidly extin- 

 guishes burning materials; 



Pentafluorid of iodin was obtained by M. Mois- 

 san without difficulty in a perfectly pure state 

 by the action of fluorin upon solid iodin. It 

 formed a colorless liquid solidifying at 80 C., 

 and boiling without "change at 97 C. Analysis 

 shows that the fluorid has undoubtedly the com- 

 position IF B , and it is noteworthy that it can 

 be distilled in a current of hydrogen without 

 any reaction taking place. This fluorid possesses 

 very great chemical activity. Most elementary 

 bodies decompose it, and it produces with com- 

 pound bodies a large number of double decom- 

 positions. Pentafluorid of iodin is decomposed 

 about 500 C., iodin being formed, and possibly 

 a new fluorid of iodin. 



A monomethylarsin the analogue in the ca- 

 codyl group of methylamin has been prepared 

 by A. W. Palmer and W. H. Dehn. Indications 

 of the existence of such a compound had been 

 obtained three years before by the reduction of 

 methyldichlorarsin ; but as this is costly and 

 difficult to prepare, a more suitable starting- 

 point was found in cacodylic acid. This, on re- 

 duction with amalgamated zinc dust and hydro- 

 chloric acid, gives the CH 8 AsHj, which is sepa- 

 rated from the hydrogen that accompanies it by 

 passing through a U-tube surrounded by a mix- 

 ture of solid carbon dioxid and ether. Mono- 

 methylarsin is a colorless, mobile liquid which 

 boils, under ordinary atmospheric pressure, at 

 2 C., and possesses the penetrating, objection- 

 able smell of cacodyl. It rapidly attacks india- 

 rubber, and combines immediately with oxygen, 

 without, however, catching fire spontaneously; 

 in this respect differing from dimethylamin. The 

 production of monophenylarsinic acid is dis- 

 cussed in the same paper. 



In the manufacture of a pigment which in 

 composition is a hydrated basic ferric oxid, 

 Fe 2 O,Fe 2 (OH) 6 , one of the first commercial ap- 

 plications is presented of those physico-chemical 

 theories which have been developed largely by the 

 study of dilute electrolysis. The waste ferrous 

 liquor derived from iron pickling generally fer- 

 rous sulfate or chlorid, with some free acid 

 is neutralized and then oxidized by the joint ac- 

 tion of air and steam. As the oxidation pro- 

 ceeds an alkali, as sodium carbonate in solution, 

 sufficient to maintain substantial neutrality, is 

 produced, and simultaneously therewith a large 

 volume of water, which is the true precipitating 

 agent. The effect is that known as hydrolysis, 

 or the decomposition by water of a salt com- 

 posed of a base and acid between which there 

 is a {rrcat disparity of strength in the present 

 instance a compound of a weak base with a 

 strong acid. By the oxidation of ferrous sul- 



fate, basic ferric sulfate is formed, and this salt 

 in the presence of a large volume of water is 

 hydrolized, yielding sulfuric acid and basic ferric 

 hydrate the pigment in question. A reaction of 

 this character would, of course, soon reach an 

 equilibrium, and the yield of pigment would be 

 but small, wherefore the gradual addition of al- 

 kali to combine with the acid as it is liberated 

 and to insure the continuance of the reaction to 

 the complete precipitation of the iron. The pig- 

 ment is bright yellow in color, but is readily con- 

 verted by heat into the several iron oxid reds, 

 and affords also a reliable base for mixed pig- 

 ments. Its absorptive capacity for oil greatly, 

 exceeds that of the standard pigments, being two 

 and a half times that of standard French ocher, 

 and seven and a half times that of white lead. 

 Its covering powers as compared with these pig- 

 ments is about proportionately high. 



Exposing powdered niobite and sugar charcoal 

 to the temperature of the electric furnace, Prof. 

 Moissan obtained a substance rich in niobium 

 and tantalum. From this tantalum was sepa- 

 rated by a series of chemical processes as a bril- 

 liant metallic mass having strong reducing prop- 

 erties and exhibiting reactions closely resembling 

 those of niobium, an increased reducing action 

 being the only difference noticed. Containing 

 not more than 0.5 per cent, of carbon, it scratched 

 rock crystal with ease. It was infusible before 

 the oxhydrogen blowpipe, which transformed 

 it rapidly into tantalic acid. It could be fused 

 in the electric furnace, but only with a very 

 powerful arc. Its density was 12.79, while the 

 density of the tantalum prepared by Berzelius 

 was 10.08, and that of Kose's tantalum 10.78. 

 Finely powdered tantalum took fire when gently 

 heated in fluorin, and gave off abundant vapors 

 of a fluorid. The element took fire in oxygen at 

 600 C., and burned with lively incandescence; 

 but no reactions took place at that temperature 

 with sulfur or the vapor of iodin. Reactions of 

 chlorin and the resultant products are described. 

 From the reactions found, taken together, it ap- 

 pears that tantalum possesses very particular re- 

 ducing properties, which cause it to resemble the 

 metalloids rather than the metals. 



A new gas derived from radium was described 

 by M. and Mme. Curie, who having placed very 

 active radium in a glass vessel and exhausting 

 and allowing the apparatus to stand, found that 

 the pressure steadily increased. When the small 

 volume of gas thus collected flowed along glass 

 tubes it made them phosphorescent, and even- 

 tually blackened them. Prompted by this ob- 

 servation, E. Rutherford and Miss H. T. Brookes 

 examined the power of radio-active substances to 

 emit radio-active particles continuously. Apply- 

 ing the rule of the inverse order of the coeffi- 

 cient of diffusion to that of molecular weight, 

 they calculated for this gas or vapor a molecu- 

 lar weight lying between 40 and 100. These 

 numbers are taken to exclude the possibility of 

 the substance being vapor of radium, for its 

 atomic weight is greater than that of barium. 

 They conclude that the emanation is in reality 

 a heavy radio-active vapor or gas. The thorium 

 emanations are also supposed to be gaseous in 

 character. The physical properties of these ema- 

 nations or gases are described as being most 

 remarkable. The radium emanation not only 

 continues for long intervals to be a source of 

 radiation which is apparently similar in character 

 to easily absorbed Rontgen rays, but in some way 

 manufactures from itself a positively charged sub- 

 stance which travels to the negative electrode and 

 becomes a source of secondary radio-activity. 



