April 6, 1893 J 



NATURE 



551 



SOCIETIES AND ACADEMIES. 

 London. 

 Chemical Society, March 2.— Dr. J, H. Gladstone, vice- 

 president, in the chair. The following papers were read : — 

 The magnetic rotation and refractive power of ethylene oxtde, 

 by W. H. Parkin. The magnetic rotation of ethylene oxide 

 is remarkably low, and the refractive power is also below the 

 calculated value. — The origin of colour (including fluorescence), 

 vii. The phthaleins and fluoresceins, by H. E. Armstrong. 

 The author has previously taken exception to the formulae 

 usually assigned to phenolphthalein and its congeners ; the 

 exhibition of colour by these substances could not be accounted 

 for by the formulae generally ascribed to them. The cor^ectnes^ 

 of the author's views has now been demonstrated by Bernthsen 

 and Friedlander independently. The former chemist has shown 

 that the rhodamines afi'ord true ethereal salts, proving that they 

 form carboxy-compounds and not lactone derivatives. Bernthsen 

 also points out that the characteristic development of colour 

 observed on adding alkali to phenolphthalein is probably due to 

 the hydrolysis and subsequent conversion of the colourless 

 lactone derivative into a quinolic compound ; the latter then 

 suffers dehydration, affording a coloured quinonoid derivative : — 



rco 



CflHiJ >0 + H,0 



(C ^1_ (C«H. . OH), 



(COoH 

 C(OH)(C6H4.0H)2 

 lCOoH (CO2H 



C«H, 



C(OH)C6H4 . OH = H,0 + CgHj [ C . C6H4 . OH 



CgH^ . OH C6H4O 



Friedlander also has lately shown that phenolphthalein and 

 hydroxylamine interact in alkaline solution with formation of a 

 hydroxime ; this and other evidence has led him to the opinion 

 that in their coloured state phenolphthalein and the allied 

 phthaleins which behave similarly towards alkalis, are all 

 quinonoid compounds. The fact that the rhodamines yield 

 ethereal salts is also remarked in a patent specificifttion by a 

 German colour firm. The author considers the recognition of the 

 quinonoid nature of the rhodamines and fluoresceins to be an im- 

 portant argument in favour of the views that fluorescence is a 

 form of colour, and that all quinonoid derivatives would be visibly 

 fluorescent were it not that the rays which cause the fluorescence 

 sometimes become absorbed in the solution. — The origin of 

 colour, viii. The limitation of colour to truly quinonoid 

 compounds. Change of colour as indicative of change of struc- 

 ture, as in the case of alizarin, by H. E. Armstrong. A 

 quinonoid compound may be defined as a hexaphene, i.e. an 

 unsaturated cycloid composed of six " elements," of which two 

 are CC'*^" groups in either para- or ortho- positions. Coloured 

 substances generally appear to fall within this definition ; the 

 few exceptions to the rule may be explained either by the 

 author's view of isodynamic change or as resulting from the 

 presence of traces of impurity. Some of the keto-chlorides 

 prepared by Zincke possess an intense yellow colour, although 

 containing the group— CCig — CO — ; it is, however, not im- 

 probable that in such substances the group CC1._, is the true 

 equivalent of the C^R " group. The usual constitution assigned 

 to alizarin does not explain its red colour, red being the cha- 

 racteristic colour of the orthoquinones ; the colour may be 

 accounted for by regarding alizarin as an isodynamic form of 

 dihydroxyanthraquinone thus : — 

 (0H)0 

 C II 



/\/\/\0H 



I I -Ml 



co' 



The red colour of the chloranilates may be explained in a some- 

 what similar manner. — Notes on optical properties as indicative 

 Df structure, by H. E. Armstrong. From a consideration of 

 the refractive and dispersive powers of the metallic carbonyls, 

 the author anticipates that quinonoid compounds generally will 

 be found to possess specially high refractive powers. There are 

 indeed experimental data supporting this view — anthracene, a 

 hydrocarbon which i; probably quinonoid in structure, having a 



NO F223, VOL. 47] 



high refractive power ; further evidence is afforded by the 

 specific refractions of the ortho- and para-nitranilines. The 

 author then proceeds to discuss the orthodox formulae for tri- 

 methylene, ethylene oxide, and diazoimide — 



CHj O NH 



HjC^CHj HaC^CHj N^An 



contrasting these substances with nitrous oxide ; he contends 

 that the above structural formulae have no real justification, and 

 that latent affinities may exist in these compounds just as in 

 carbonic oxide. Thus nitrous oxide mav be regarded as 

 <N - O - N >, and diazoimide as < N -NH - N >. The 

 influence exerted by the ethenoid and benzenoid groups in 

 organic substances upon their refractive and dispersive powers, 

 is also considered. — The origin of colour, ix. Note on the 

 appearance of colour in quinoline derivatives and of fluorescence 

 in quinine, by H. E. Armstrong. From considerations based 

 upon the previous notes, the author shows that any amido- 

 derivative of quinoline might become quinonoid in structure, 

 owing to a change from the centric to an ethenoid form, and 

 would hence be coloured. Similarly, an ethenoid form of 

 naphthalene would be quinonoid ; it is therefore possible that 

 the fluorescence exhibited by many derivatives of this hydro- 

 carbon is characteristic of the pure substances, and does not 

 always originate in impurities. — The ethereal salts of glyceric 

 acid, active and inactive, by P. Frankland and J. MacGregor. 

 The authors have prepared and characterised a number of 

 ethereal salts of inactive and laevo-glyceric acid ; they point out 

 regularities between the rotatory powers of the active salts of a 

 somewhat similar nature to tho»e observed amongst the ethereal 

 salts of tartaric acid. —Formation of the ketone 2 : 6-dimethyl- 

 i-ketohexaphane, by F. S. Kipping. On distilling the calcium 

 salt of dimethylpimelic acid with soda lime, an oil is obtained 

 which contains a ketone of the composition C8H14O. This 

 ketone is apparently a dimethylketohexamethylene ; it is doubt- 

 less a homologue of the ketone recently prepared by von 

 Baeyer by distilling calcium pimelate with soda lime. — Note on 

 the interactions of alkali-metal haloids and lead haloids, and of 

 alkali-metal haloids and bismuth haloids, by "Eleanor Field. 

 By boiling potassium or ammonium iodide with lead haloids 

 in aqueous solutions, double compounds are obtained, whose 

 composition depends upon the proportions in which the con- 

 stituents are used. Salts of the compositions, 3PbIo4KI, 

 3Pbl24NH4l, PblaSPbClj, PbljSPbClj, and Pbl22PbBr2, are 

 described. The in'teractions of haloid salts of the alkali metals 

 with bismuth haloids lead to the formation of compounds 

 having the following compositions — BiBrCl4K2, BiClBr4K.2> ^^^ 

 BiCl3Br3(NH4)3. The composition of the products obtained 

 depends, not only on the proportions in which the reacting salts 

 are employed, but also on the nature of the halogens and the 

 metals. — An isomeric form of benzylphenylbenzylthiourea by 

 A. E. Dixon. Phenylthiocarbimide and dibenzylamine interact 

 to form the compound PhN : C(SH) . '^{Z-iVi-j)^, isomeric 

 with the thiourea C^H-N : C(SH) . NPh . C7H7. melting at 

 103°, previously obtained by the author from benzylthiocarbi- 

 mide and benzylaniline ; the new substance melts at 145-146°. 

 - A new atomic diagram and periodic table of the elements, by 

 R. M. Deeley. The author constructs a new atomic diagram 

 of the elements by plotting "volume heats" against "volume 

 atoms" The volume heats are the products of the specific heats 

 and densities, whilst the volume atoms are obtained by dividing 

 relative density by atomic weight. 



Paris. 

 Academy of Sciences, March 27.— M. Loewy in the 

 chair. — The two candidates selected as competitors for the place 

 of Astronome Titulaire at the Paris Observatory were : In the 

 first place, M. Prosper Henry ; in the second, M. Paul Henry. 

 — On the construction of the chart of the heavens, and the 

 determination of the co-ordinates of the centres of the nega- 

 tives, by M. Lcewy.— On the organic substances constituting 

 vegetable soil, by MM. Berthelot and Andre. " Humus " may 

 be defined as that portion of the remains of vegetation which 

 resists the action of the air and lower organisms, and remains 

 as an insoluble residue in the soil, supplying the roots of the 

 higher plants with nitrogen, sulphur, phosphorus, alkalies, &c 

 One specimen of earth freed from all visible plant remains, 

 cellulose, and carbohydrates, taken from the experimental soil 

 of the Vegetable Chemistry station at Meudon, contained I9'i 

 parts of organic carbon, i -5 of hydrogen, 1 7 of nitrogen, 1 1 '^ 

 of organic oxygen, total 34*2 parts of oi^anic matter. Some of 



