CHEMISTRY. (CHEMICAL PHYSICS.) 



higher point than either of the components, and 

 show two irregularities indicative of two distinct 

 compounds. In these mixtures it appears that 

 the component that predominates to a consider- 

 able extent is always a solvent to the compound 

 formed with the other component; but as the 

 proportion of the other component is increased, 

 the condition becomes reversed. Interesting re- 

 sults have been obtained by observing, not only 

 the freezing point, but the point where the whole 

 mass solidifies, so that for every mixture the exact 

 composition of the mass from which the com- 

 pound has separated and of the separate com- 

 pound is indicated. Rontgen-ray photography 

 has also been utilized to demonstrate the forma- 

 tion of these intermetallic compounds. A long 

 list of known and supposed alloy compounds is 

 given in the report; and it appears that the 

 atomic relations generally assumed by chemists do 

 not hold in the case of the alloys. 



In presenting the foregoing report Mr. F. H. 

 Neville held that intermetallic compounds may 

 be compared with the unstable compounds of the 

 halogens to each other and with sulphur. They 

 often bear a great superficial resemblance to their 

 constituent elements, and appear to show marked 

 dissociations or to form systems in true equili- 

 brium with the liquid mixture of their components. 



An experiment described by Schonbein nearly 

 forty years ago in which on shaking lead amal- 

 gam with air and water equivalent quantities of 

 lead oxide and peroxide of hydrogen were formed 

 has been followed in recent years by many iso- 

 lated cases indicating a phenomenon of autoxi- 

 dation or simultaneous oxidation by air of two 

 substances, one of which is incapable of being 

 oxidized by air alone. The formation of peroxide 

 of hydrogen in such cases is proved by the re- 

 searches of Bamberger, and of Manchot in par- 

 ticular. The probability has been suggested by 

 Engler that in all these instances the reaction is 

 simultaneous, half of the oxygen molecule going 

 to oxidize the substance present, and the other 

 half to form hydrogen peroxide. In many cases 

 the formation of the latter substance is difficult 

 to prove, on account of the secondary oxidizing 

 action in the substance used. Dr. H. Biltz has de- 

 scribed experiments on the oxidation of hydra- 

 zone of debromoxylbenzaldehyde in alkaline solu- 

 tion by air at the ordinary temperature, and in 

 this case he has been able to prove that the 

 amount of oxygen in the hydrogen peroxide 

 formed is exactly equal to the oxygen used up 

 by the hydrazone. 



Prof. Brauner said at the German scientific 

 meeting in September, 1809, concerning the posi- 

 tion in the periodic system of the elements of the 

 rarer earths, that he considered that the position 

 indicated by the fourth group and the eighth 

 series must be assigned to a group of three ele- 

 ments cerium, 140; praseodymium, 140.8; neo- 

 dymium, 143.C. This conclusion was based in a 

 great measure on the study of the higher oxides. 

 The author considered that the oxides Pr 2 O 4 

 and Nd 2 O 4 belong to the oxides of the PbO 2 or 

 ozonic type that is to say, that the metals in 

 these oxides are tetravalent, and the oxides cor- 

 respond to Ce.,O 4 . At first sight the oxides ob- 

 tained by precipitation with hydrogen peroxide 

 should belong to the second, H 2 O 2 , or autozonic 

 type of oxide. Prof. Brauner found that on re- 

 peating this experiment at low temperatures the 

 hydrates of true superoxides were formed, pos- 

 sessing the formula Pr 2 O 5 and Nd 2 O s , and losing 

 oxygen with great ease. 



Chemical Physics. The record of the study 

 of radio-active substances, as it is summarized in 



a paper read by H. Carrington Bolton before the 

 Chemical Society of Washington, and published 

 in the Journal of the American Chemical Society, 

 begins with the announcement by Becquerel that 

 the salts of uranium emit invisible radiations 

 capable of discharging electrified bodies and of 

 inducing skiagraphic images on sensitive plates. 

 Other experimenters found that a number of other 

 substances had the power of emitting " Becquerel 

 rays": Mr. Henry, phosphorescent zinc sulphide; 

 Niewcngloski, insolated calcium sulphide; Troost, 

 artificial hexagonal blende; Schmidt, thorium 

 compounds. Mme. Curie, studying the subject 

 with her husband and using a special apparatus, 

 found the property in a number of minerals, and 

 observed especially that pitchblende contained a 

 substance analogous to bismuth, which emitted 

 rays 4,000 times stronger than those of uranium. 

 She called this substance polonium. Afterward 

 Mme. and M. Curie discovered a second radio- 

 active body in pitchblende which they called 

 radium. This hitherto unknown element was 

 found to accompany barium in analytical separa- 

 tions. Its chloride is wholly soluble in water, and 

 it responds to the usual tests for barium. Its 

 spectrum shows the lines peculiar to barium, and 

 other lines peculiar to itself. Attempts to sepa- 

 rate barium from radium have been unsuccessful, 

 but a salt has been obtained having 900 times the 

 activity of uranium. The rays emitted by the 

 two new substances possess luminosity and 

 actinic and skiagraphic power, and render the air 

 through which they pass a conductor of elec- 

 tricity. In some other respects polonium and 

 radium manifest noticeable differences in be- 

 havior. The rays emitted by these substances 

 have the power, when in contact with inert bodies, 

 of communicating their activity to them, and of 

 exciting phosphorescence in gems and minerals 

 (barium sulphide, calcium sulphide, etc.). 

 Mme. and M. Curie have observed that this in- 

 duced property continues for a considerable time. 

 In fluorite the phosphorescence remained twenty- 

 four hours after the influence of radium had been 

 removed. The authors, having obtained samples 

 that were from 5,000 to 50,000 times more power- 

 ful than uranium in. communicating radio-active 

 energy to inactive bodies, observed while experi- 

 menting with them that the induced activity im- 

 mediately after exposure varied between one and 

 fifty times that of uranium, but was reduced two or 

 three hours later to one tenth its original value. A 

 research was made to determine whether induced 

 radio-activity is due to traces of radio-active mat- 

 ter carried in the form of vapor or powder to the 

 exposed surface. The fact that no differences 

 were found in the radio-activity of the various 

 substances experimented upon seemed to favor 

 this supposition; but the authors believe they 

 have proved the theoiy to be incorrect, and that 

 real induced radio-activity exists. They regard 

 the phenomenon as a kind of secondary radiation 

 due to Becquerel's rays, but differing from the 

 phenomenon which is known to exist for Rontgen 

 rays. " Indeed, the secondary phenomenon of 

 Ro'ntgen rays, as known at present, becomes ap- 

 parent at the moment when the body is struck 

 by the Rontgen rays, and ceases abruptly with the 

 cessation of the latter." The energy imparted to 

 metallic plates was not removed by washing in 

 water, although radium chloride is soluble in 

 water. Mme. and M. Curie have further found 

 that the rays emitted by radiferous salts of bari- 

 um are very active, and are capable of transform- 

 ing oxygen into ozone. The radiferous products 

 necessary for the production of ozone are all very 

 active and very luminous, the phenomenon ap- 



