490 



SCIENCE. 



[N. S. Vol. XII. No. 300. 



istry, especially in connection with the rarer 

 elements. The ultimate aim of this work is to 

 determine more accurately the relation of the 

 elements to each other, and incidentally it is 

 doing much to clear up the Periodic Law. 

 Considering the gaps and discrepancies in the 

 work that has been done upon the element 

 thallium since its discovery by Crookes in 1861, 

 it is hardly strange that two workers should 

 have selected this for investigation. In the 

 last American Chemical Journal a paper by Pro- 

 fessor Cushman, of Bryn Mawr, takes up the 

 first chapters of a study of the halogen com- 

 pounds of thallium ; while the last number of 

 the Zeitschrift fiir anorganische Chemie contains 

 a long article by Professor Richard Jos. Meyer, 

 of Berlin, on trivalent thallium, with especial 

 reference to the halogen compounds and the 

 nitrates. There are some very considerable 

 discrepancies between the observations of these 

 two chemists, which will doubtless be cleared 

 up by further study and by comparison. The 

 most important result of Cushman's is the 

 preparation of two isomeric compounds of the 

 formula Tl^ClgBrj, or as they may be written, 

 TlClsSTlBr and TlBrsSTlCl. Isomerism of 

 this character, while common in organic chem- 

 istry, is very rare in inorganic chemistry, and 

 many have asserted that it does not exist. 

 Meyer has added to our knowledge a large 

 series of new thallium salts, and brings out 

 very beautifully the analogies which exist be- 

 tween thallium and gold. As both these 

 authors are continuing their researches, there 

 may be expected decidedly interesting and 

 valuable contributions to our knowledge of 

 thallium in the near future, as each profits by 

 the work of the other. 



A NEW and important addition to our 

 knowledge of the chemistry of radium appears 

 in the Comptes Rendus, from the pen of 

 Madame Curie. By carefully fractioning many 

 samples of radiferous barium, she has gradu- 

 ally accumulated small quantities of nearly 

 pure radium ; indeed, one specimen of a few 

 centigrams was pronounced practically pure 

 and was used for spectroscopic observations. 

 With a specimen of 0.4 gramme concentrated 

 radium, which, however, contained more or less 

 barium, an atomic weight determination was 



made. This gave an atomic weight of about 

 174, while the atomic weight of barium is 

 137.5. This figure of 174 is a minimum, and 

 M. Demargay considers from spectroscopic ob- 

 servation of the specimen that there was rather 

 more radium in it than barium. In any case it 

 would follow that the atomic weight of radium 

 must be decidedly higher than 174. This would 

 seem to be very strong evidence that radium is 

 an individual element and not a peculiar form 

 of barium. 



J. L. H. 



ACADEMEI DEI LINCEI OF R03IE. 

 At the anniversary meeting of the Academei 

 dei Lincei of Rome, Professor Cremona read a 

 biographical notice of Professor Beltrami, who 

 was president of the Academy at the time of 

 his death. The prizes of the Academy an- 

 nounced in the Atti are summarized in Nature 

 as follows : For the Royal prize of 1000 francs 

 for normal and pathological physiology six can- 

 didates entered, and a large number of essays 

 of considerable merit were submitted by them. 

 The prize has been adjudged to Professor 

 Giulio Fano, of Florence, for sixteen papers, 

 dealing, amongst other subjects, with the 

 physiology of the embryonic heart, the doc- 

 trine of experimental psychology, the organ of 

 hearing, the graphic registration of respiratory 

 chimism and reflex movements, the latter 

 being a continuation of previous researches on 

 the organs of Emys Europea. Of the six candi- 

 dates for the Royal prize for geology and 

 mineralogy, two were considered worthy of 

 the award, which was therefore divided 

 equally between them. One of the successful 

 candidates, Professor De Lorenzo, chose geo- 

 logical subjects, and sent in about twenty 

 essays, the most important of which dealt with 

 the Trias of the environs of Lagouegro, the 

 Mesozoic mountains of Lagonegro, geological 

 observations on the Apennines of the southern 

 Basilicate and geological studies of the south- 

 ern Apennines. Professor Giorgio Spezia's 

 work, on the other hand, was entirely miner- 

 alogical, dealing with the influences of tem- 

 perature and pressure, respectively, on the 

 chemical metamorphism of rocks and minerals. 

 From a long and laborious series of experi- 



