CHBM18TRT, 



79 



been verified by the researches of M. V. < >s- 

 iiiniiil, from which it appears that foreign bodies 

 of -mall atomic volume tend to cause iron to 

 assume or remain in that one of its forms which 

 h;is I he Mimllfst atomic volume. Bodies of great 

 atomic volume produce the opposite effect. 



It was found in the experiments of Profs, 

 l.iveini,' und I'ewar on the explosion of ga.-es 

 under high pressure that the luminosity of the 

 Maine steadily increased with increase of pressure. 

 When hydrogen was exploded with excess of 

 oxygen, large (|ii!intities of nitrogen peroxide, 

 were formed from the nitrogen present as im- 

 purity in the oxygen. The water formed con- 

 tained :! per cent, of nitric acid. With excess 

 of hydrogen small quantities of ammonia were 

 formed. It was difficult to maintain the oxy- 

 hydrogen flame in an atmosphere of carbon di- 

 oxide if the pressure exceeded two atmospheres. 

 Kxperiments were, also made with ethylene and 

 cyanogen exploded with oxygen. 

 ' The experiments of the committee of the Brit- 

 ish Association on the properties of solutions 

 have been completed as to the solubility of a salt 

 in a solution of another salt of known strength. 

 In general, a salt is less soluble in a salt solution 

 than in pure water. But KX0 8 in solution of 

 NaNOj offers an exception. 



In a paper on electromotive force, Prof. C. L. 

 Speyers referred, in the American Association, 

 to the absence of a satisfactory explanation of 

 the relation between chemical and electrical en- 

 ergies, and gave reasons for thinking that a con- 

 nect ion exists between the electromotive force 

 developed in a cell and the dissociation of the 

 salt in solution. 



New Substances. Chlorofluoride of phos- 

 phorus, PF,Cl a . is a new gaseous compound pro- 

 duced by M. Poulenc by adding chlorine to phos- 

 phorus trifluoride. The combination is attended 

 by a contraction of one half. Phosphorus chloro- 

 fluoride is a colorless, incombustible gas, possess- 

 ing a powerfully irritating odor. It is instantly 

 absorbed and decomposed by water and by solu- 

 tions of alkaline or alkaline earthy hydrates. It 

 liquefies under ordinary pressures at 8 C., and 

 is dissociated at 250 C., or by the induction spark 

 into gaseous pentafluoride and solid pentachlo- 

 ride of phosphorus. It is absorbed by absolute 

 alcohol with production of a compound possess- 

 ing a penetrating odor, which burns with a bright 

 flame bordered with green, and leaves a white 

 rcM.'uc of phosphoric acid. 



A phosphorous oxide supposed to exist in ad- 

 dition to the pentoxide formed when phosphorus 

 is burned in air or oxygen has been described as 

 a white, amorphous powder of the composition 

 PjO s . very voluminous, somewhat more readily 

 fusible than the pentoxide, and instantly dis- 

 solved with great rise of temperature by water, 

 with formation of phosphorous acid. 'Studies 

 pursued during three years by Prof. T. B. Thorpe 

 and A. K. Tutton show that as obtained by them 

 it is. at temperat ures not exceeding 22 C., a pure- 

 white crystalline solid, compact and heavy, firm 

 and wax-like in character. Its most striking 

 property is the ease with which it melts, the 

 warmth of the hand which holds the vessel con- 

 taining it being more than enough to convert it 

 into a liquid. Its melting point is 22'5 C., and 

 when placed in that temperature it becomes a 



clear, colorless liquid, very mobile, but some- 

 what heavy. It is best preserved in sealed glass 

 tubes, the air in which has l>een replaced by car- 

 bon dioxide or nitrogen. When cooled in such 

 a tube the oxide rapidly resolidifies, with large 

 crystals shooting out in all directions till the 

 whole is one compact mass of interlacing crys- 

 tals. The vapor of phosphorous oxide possesses 

 a characteristic odor, which appears to be the 

 same as that noticeable about a lucifer-mateh 

 factory. But the solid and the liquid are con- 

 stantly vaporizing, and hence the odor is strong- 

 ly marked. Instead of reacting with violence 

 with water, phosphorous oxide is indifferent to 

 it, and dissolves very slowly in it. Warmed with 

 water nearly to the boiling point, it evolves spon- 

 taneously inflammable phosphoretted hydrogen 

 with a loud explosion and the formation of red 

 phosphorus and phosphoric acid. It is believed 

 that the disease of the lower jaw suffered by per- 

 sons engaged in lucifer-match making is caused 

 by the vapor of this substance. 



During the preparation of specimens of crys- 

 talline and other forms of silicon, H. N. Warren 

 obtained a most curious form of that substance, 

 which appears, when tested analytically, to be 

 composed of graphitoidal silicon, constituted so 

 as to give perfect and well-developed oblique 

 octahedral crystals. The peculiar form first ap- 

 peared on subjecting potassium silicofluoride to 

 a most intense heat in contact with impure alumi- 

 num. A method, though uncertain, was found 

 of obtaining it in larger quantities, the product 

 of which was pure silicon, insoluble in all acids 

 except hydrofluoric, and infusible. The crystals 

 look like the crystals of cast iron which are some- 

 times met with on breaking a pig of that sub- 

 stance. The largest measured more than half an 

 inch across the faces, and were as perfect as a 

 crystal of alum. 



A series of double compounds of phenanthra- 

 quinone with metallic salts have been described 

 by Prof. F. R. Japp and A. E. Turner. Among 

 them are those with ZnCl a , which crystallizes in 

 dark, reddish-brown needles ; with IIgCl s , crys- 

 tallizing in red, obliquely truncated prisms: and 

 with Hg(CN)n, crystallizing also in red forms. 

 A similar compound was obtained from mercuric- 

 chloride and /3-naphthaquinone ; but double com- 

 pounds could not be obtained from certain para- 

 quinones or a-diketones, whence it was inferred 

 that they are derivable only from orthoquinones. 

 The intense color of the double compounds indi- 

 cates that in them the quinone preserves its dis- 

 tinctive character. 



A new acid, chromosulphuric, H,Cr,(S0 4 )4, 

 or its salt, described by Mr. Recoure. appears to 

 be formed by the direct combination of a pre- 

 viously described isometric form of chromic sul- 

 phate with one equivalent of sulphuric acid, or 

 of a metallic sulphate. The acid has been ob- 

 tained in the solid state, combined with 11 mol- 

 ecules of water. It is a green powder, which is 

 very hygroscopic and deliquesces rapidly in 

 moist air, but is permanent in a dry atmosphere. 

 Its solution is bright green when freshly pre- 

 pared, but changes to blue on standing, and after 

 a few days passes into a violet-colored solution 

 of ordinary chromic sulphate mixed with free 

 sulphuric acid. The potassium salt hasltoen ob- 

 tained in the solid state, combined with 4 mole- 



