Oct. 4, [883] 



NATURE 



55i 



ance of some Fraunhofer lines from spots has been attributed 

 with much probability to the emission of the upper regions of the 

 -un's atmosphere just balancing the absorption below : the rays 

 lor which this happens are those of vapours of low tension 

 (corresponding to Mr. Lockyer's long lines) e nitted by the 

 elements in their least complex state of aggregation. The 

 singular ray with wave-length 4923, which is a line of iron of 

 high vapour tension, but behaves in the sun as a line of low 

 vapour tension, being frequently seen high up in solar storms 

 and disappearing from spots, probably belongs to some other 

 metal as well as iron. 



Mr. R. Meldola read a paper on The Colouring Matters of 

 ike Diazo- Group, in which he gave an historical sketch of this 

 important class of bodies discovered by Dr. Griess, and pro- 

 ceeded to describe a number of new compounds in which the 

 diazo-grouping occurred three times. These compounds pre- 

 pared by the author yielded excellent dyes, specimens of which 

 were exhibited. The great importance of these new products 

 was shown by the fact that since their introduction the cochineal 

 1iK.lu-.t1y had gradually declined. 



Mr. II. B. Dixon exhibited tubes in which a dried mixture of 

 carbonic oxide gas and oxygen was submitted to the electric 

 The tubes were shaped like the letter W, the two outer 

 being open and sealed with mercury in the two lower 

 bends. In one arm of each tioe anhydrous phosphoric acid had 

 been introduced to dry the gaseous mixture. The tubes had 

 been so charged for a period of three days. On passing the 

 spark at the top of the central bend, a very slow and quiet com- 

 bustion was propagated down the tube in which no phosphoric 

 acid had been placed, but no combustion was propagated down 

 the tube containing the phosphoric acid. In an experiment with 

 another similar tube, only a small fraction of the mixture ignited 

 in one arm. Water was then introduced by a pipette into the 

 mixture, and after the steam had diffused, the spark was passed, 

 producing a loud explosion. 



Prof. A. W, Williamson in discussing the Chemical Constitu- 

 tion of Matter remarked that when any sufficiently careful 

 attempt has been made to decompose one of our elementary 

 substances this attempt has always failed. Referring to Front's 

 hypothesis that the atomic weights of the elements were exact 

 multiples of that of hydrogen, Dr. Williamson showed that this 

 idea had bees fruitful because it had led chemists to make most 

 accurate and conscientious determinations of atomic weights. 

 The result of the labours of MendeleefT, Lothar Meyer, and others 

 has shown that the elements belong to a natural family, and 

 has given an authority to the established weights which could not 

 be assigned t j them previously on chemical or physical ground-. 

 When chemists speak of matter, they always limit themselves to 

 that which can be » eighed : it would be better to throw off that 

 limitation and not hamper our ideas with a condition which may 

 Some day have to be removed. What many chemists have 

 led as the most fundamental property of matter, its weight, 

 may not be an inherent property in the matter itself, but may 

 depend on forces reacting between the "matter" and the ether 

 surrounding it. All that we know about the atomic weight of 

 atoms is not inconsistent with varieties among individual atoms, 

 but only proves that the average weight of large aggregates of 

 atoms is the same. 



l'rof. Dewar read papers, by himself and Mr. A. Scott, on The 

 Atomic Weight of Manganese and on The Molecular Weights of 

 Substituted Ammonias, in the htter of which the authors pointed 

 out the advantage of using the molecular weights of diese coin- 

 pounds for accurately determining the relation between the atomic 

 weights of bydrog n and carbon of which elements several 

 atoms are contained in the introduced radicle. The authors 

 conclude from their experiments that if oxygen be taken as 16, 

 the atom of hydrogen must be less than unity, and not larger, as 

 is the generally received opinion. 



l'rof. W. Ramsay, in a paper on The Application of Bisulphide 

 oj Carbon to the Scouring of Wool, drew attention to a curious 

 difference in the quality of the bisulphide manufactured in France 

 and England. 



The Rev. W. A. Irving exhibited tubes in which trioxide of 

 phosphorus had been sealed up and exposed to sunlight. The 

 tubes contained dark crystals of phosphorus. The author stated 

 that on opening the tubes he found pentoxide of phosphorus 

 present, and argued that the sunlight had decomposed the tri- 

 oxide into free phosphorus and the pentoxide. In the discussion 

 it was suggested that free phosphorus might have been sealed up 

 together with the oxide, and have changed its condition on 

 exposure to sunlight. 



Prof. Dewar pointed out an important relation between the 

 cri'ical temperature and pressure of volatile liquids and their 

 molecular volumes. The ratio of the critical pressure to critical 

 temperature is proportional to the molecular volume, so that the 

 determination of the critical temperature and pressure of a 

 substance gives us a perfectly independent measure of the 

 molecular volume. Prof. Dewar pointed out the great advantage 

 of e nploying a liquid of low critical temperature and pre-sure 

 such as liquefied marsh gas for producing exceedingly low 

 temperatures. He hoped to be able to approach the absolute 

 zero by the evaporation of liquefied marsh gas whose critical 

 temperature was less than - too Centigrade, and whose 

 critical pressure was only 39 atmospheres.— Sir W. Siemens 

 hoped Prof. Dewar would soon succeed in producing a 

 temperature near to the absolute zero, as he had the greatest 

 desire to test at such a low tern, erature the magnetic and electric 

 behaviour of metals. 



Dr. Gladstone, in a paper written in conjunction with Mr. 

 Tribe, on The Electrolysis of Dilute Sulphuric Acid in Secondary 

 Batteries, was led to the conclusion that besides the molecular 

 change in the electrolyte, there was also an actual passage of 

 sulphuric acid into the limb containing sulphate of copper. No 

 data exist to decide the question whether it is sulphuric acid or 

 some hydrate of it that is electrolysed, but analogy would lead to 

 the conclusion that it is sulphuric acid. 



Mr. H. Brereton Baker, in a paper on The Alleged Direct Union 

 of Hydrogen and Nitrogen, described the carefully conducted 

 experiments he had made with nitrogen, derived without heat 

 from the air, and pure hydrogen. These gases led over hot 

 platinum sponge gave no trace of ammonia. He found that, in 

 an apparatus similar to that used by Mr. Stillingrleet Johnson, 

 the oxides of nitrogen produced by the passage of hydrogen 

 through the nitrate of silver solution used to purify it were not 

 completely arrested by the ferrous sulphate absorbers, so that 

 the ammonia produced in Mr. Johnson's experiments was 

 doubtle-s due to the action of these oxides on hydrogen in 

 presence of hot platinum. 



Messrs. Friedel and Crafts communicated a paper on The 

 Decomposition of Hydrocarbons by Aluminic Chloride. Chloride 

 of aluminium is not only a synthetical agent but also a reducing 

 agent causing the snb-titution of hydrogen for methyl, ethyl, 

 &c. For instance naphthalin distilled with 25 per cent of 

 aluminic chloride gave a distillate of benzene and hydrides of 

 naphthalene. Benzene, heated to 235° C. in a sealed tube with 

 the chloride, gave off marsh gas on opening, and the contents of 

 the tube on distillation with water gave hydrocarbons boiling at 

 from So" to 160°. Diphenylmethane. distilled with chloride, 

 gave a distillate containing benzene and toluene. Triphenyl- 

 methane distilled with more than half its weight of chloride gave 

 only benzene. Hexamethyl oenzene heated with one-third its 

 weight of chloride gave off plenty of a non-illuminating gas ; from 

 the residue crystals of durene were deposited. In the case of 

 the poly-methyl benzenes one or more methyl groups are replaced 

 bv hydrogen with the formation of very little hydrochloric acid. 

 The same equation previously adopted to explain the synthesis 1 11 

 hydrocarbons by aluminic chloride, is sufficient to explain the 

 present decomposition :--C,.H, ; + AI a Cl e = C g H B .Al a Cl 6 + HC1. 

 The compound I ,11 .. A1..CI,, is broken up by heat into diphenyl 

 and aluminous chloride ; the latter is decomposed by the free 

 hydrochloric acid into aluminic chloride and hydrogen, and the 

 hydrogen thus set free exerts the reducing action. The Section 

 recommended the paper for publication in extenso in the 

 Transactions. 



Prof. B. Warder of Ohio, U.S.A., communicated a short 

 paper called Suggestions for Computing the Speed of Chemical 

 Reactions, lie recommended for unit of volume the cubic centi- 

 metre, for mass the chemical equivalent expressed in milligrams, 

 and for time the hour. Prof. Warder drew attention to the fact 

 that many determinations of the rate of etherification had been 

 published for twenty years, and yet no mean value of the "rate- 

 constant " had been worked out. Such calculations might fitly 

 be undertaken by students at colleges, and the Chemical Section 

 of the Ohio Institute had begun such work and invited the 

 assistance and cooperation of cheaiists engaged in teaching. 



Mr. P. M. Parsons gave an account of different varieties of 

 manganese-bronze prepared by heating copper with ferro-nian- 

 ganese. The spiegeleisen, as in the Bessemer process, removes 

 the oxygen from the copper, w ith which part of the manganese 

 forms an alloy of extraordinary tensile strength. One of the varie- 

 ties, capable of re.-isting a great transverse strain, is largely em- 

 ployed for making screw-propellers. These are cast in sand. 



