108 



CHEMISTRY. (CHEMICAL THEORY.) 



try, M. Casimir-Perier consented to head a new 

 Cabinet as Minister of Foreign Affairs, which 

 post hi- filled without mishap until the President 

 to please whom lit- had given up his tranquil 

 and honorable oflire and accepted the invidious 

 and troubled one of Premier was assassinated, 

 .June '24, isjil. Within three days, as the Con- 

 stitution prescribes, the two Chambers met in 

 ( '< >ngress to choose a new chief magistrate. Casi- 

 mir-Perier was elected, June 27, on the first bal- 

 lot, by 4.")1 votes out of 852 ; the candidate of the 

 Radicals and Socialists, M. Brisson, receiving 194, 

 and M. Dupuy 95. He resigned in January, 1895. 

 See FRANCE. 



CHEMISTRY. Chemical Theory. A re- 

 view of the progress that has been made during 

 the past few years in stereo-chemistry has been 

 published by Prof. Victor Meyer. The earlier 

 portion of Prof. Meyer's memoir is devoted to 

 the development of the idea of the symmetric 

 carbon atom, and the growth of the conviction 

 that the occurrence of isomeric compounds rep- 

 resented by the same constitutional formula 

 compounds like the three lactic acids, which 

 differ only in their action upon polarized light, 

 and very slightly in other physical properties 

 could be accounted for only by the different spa- 

 tial arrangement of the atoms in the molecule. 

 The fundamental assumptions of Van't Hoff are 

 very clearly expressed, and the possibilities of 

 isoinerism by change in the relative positions of 

 the various groups attached at the four corners 

 of the hypothetical carbon tetrahedron are fully 

 illustrated. A striking example is afforded in 

 this connection by one of the results of the re- 

 searehes of Emil Fischer in the sugar group, by 

 which we an: made acquainted frith no less than 

 i:> distinct sugars, all of which are represented 

 by the formula CII 2 OH, (CHOH) 4 CH a OH. The 

 id section of the paper is devoted to the 

 stereo-isomerism of the derivatives of ethylene, 

 which has been worked out by Wislicenus. The 

 simple explanation on the lines of the new 

 theory of the remarkable and long-discussed 

 "f the isomeric acids, maleic and fumaric, 

 i- rcfcrn-d to, and a similar explanation is ap- 

 plied to numerous other and more complicated 

 derivatives of ethylene. The third section deals 

 with the peculiar 'nature of the stereo-isornerism 

 of closed chain compounds such as the polymer- 

 i/.ed tri-aldehydes. It is then shown that carbon 

 is not peculiar in lending itself to stereo-isorner- 

 ism, but, that the pcntavalent nitrogen atom is 

 iki-wisc capable of furnishing isomers which 

 differ structurally merely in the relative posi- 

 tions occupied by the 5 attached atoms or 

 ipe. The Btereo-isomerisra of nitrogen com- 

 pounds is shown, however, to be largely influ- 

 enoed by the weight and complexity of the 5 

 attached groups The discovery of a second 

 dioiime of ben/il by Uoldschmidt gave a great 

 impulse to the study of nitrogen compounds 

 containing tin- gTOUp C f N, termed oximes; and 

 the number of stereo-iMnneric oximes which 

 have subsequently been isolated bear remark- 

 able testimony to the use of ;l theory in stimu- 

 lating research. 



As a further contribution to the discussion of 

 this subject. Dr. Werner, in a treatise on the 

 nature of the isotnerism of the numerous am- 

 moniacal compounds of cobalt, platinum, and 



other metals, shows that the complex relations 

 of these substances are capable of a strikingly 

 simple explanation upon the assumption of dif- 

 ferent arrangements of the various atoms am" 

 groups in space. The foundations of a sterec 

 chemistry of platinum are laid by assuming tl 

 atom of the metal to occupy the center of 

 regular octahedron, to the 6 corners of whk 

 the various groups are attached. In this man- 

 ner the existence of the 2 isomeric series of com- 

 plex compounds of the composition Pt(N.H 3 ) 2 X 4 

 is accounted for, the difference between th'.'in 

 being brought about by a difference in the rela- 

 tive positions of the 2 N.H S groups. It thus 

 appears, says *' Nature," " that the great concen- 

 tration of research upon the organic compounds, 

 which has been the salient feature of the chem- 

 ical progress of the last twenty years, has had 

 the fortunate effect of so enlightening us as to 

 the internal structure of chemical molecules as 

 typified in carbon compounds, that the remain- 

 ing complex problems of inorganic chemistry 

 may now be attacked with much greater likeli- 

 hood of success." 



The conclusions are drawn from the experi- 

 ments of Dr. Frank Clowes upon atmospheres 

 that extinguish flame : (1) That the extinction of 

 a flame depends not only upon the quantity, but 

 also on the quality of the extinctive gas present 

 in the air, carbon dioxide uniformly exerting a 

 more powerfully extinctive effect than nitrogen. 

 (2) That wick-fed flames burning different com- 

 bustibles show a remarkable uniformity in the 

 minimum proportion of an extinctive gas in air 

 necessary for their extinction. (3) That this uni- 

 formity is not shown by flames fed by a gas 

 burning from a jet, and no simple relation is 

 apparent in the case of the gas-fed flames be- 

 tween the proportion of oxygen present in the 

 diluted air and the proportion of oxygen requisite 

 for the complete combustion of the gas. (4) That 

 the hydrogen flame requires for its extinction the 

 presence in air of a very high proportion of ex- 

 tinctive gas ; it may, therefore, be advantageous- 

 ly used as an auxiliary flame for maintaining an 

 oil flame in the foul air of a mine or other local- 

 ity. (5) Since an ordinary candle flame or oil 

 flame is extinguished by the presence of about 

 15 per cent, of carbon dioxide in air, and air con- 

 taining more than 25 per cent, of carbon dioxide 

 has been breathed with perfect safety for more 

 than an hour, the extinction of an ordinary oil 

 or candle flame in any particular atmosphere 

 must not be taken as proof that that atmos- 

 phere contains so much carbon dioxide as to be 

 dangerous to life when it is breathed. (6) A more 

 satisfactory indication of the presence of a dan- 

 gerous proportion of carbonic dioxide is fur- 

 nished by the change of color of the hydrogen 

 flame from reddish to blue gray. This" change 

 begins when 2 per cent, of carbon dioxide is 

 present in the air ; it becomes very pronounced 

 as the proportion of the gas present increases. 

 When 80 per cent, or upward is present the 

 flame is of a pronounced blue color, and also in- 

 creases in height with the increased proportion 

 of the gas to an extent which is easily measured 

 on a scale. 



The remarkable fact that gaseous oxygen 

 sometimes exhibits more energetic chemical ac- 

 tivity in the dilute than in the more coneen- 



