314 



SCIENCE. 



[N. S. Vol. XII. No. 295. 



De. John Gtjiteeas, who resigned the chair 

 of pathology in the University of Pennsylvania 

 to fill a similar position in the University of 

 Havana, has established there a journal enti- 

 tled Bevista de Medicina Tropical. 



DISCUSSION AND COBBESPONDENCE. 



THREE FORGOTTEN NAMES FOE BIEDS. 



In Museum Leskeanum Begnum animale quod 

 ordine systematico disposuit atque descripsit, D. L. 

 Gustavus Karsten, Vol. I., Leipzig, are proposed 

 three names for birds which appear to have 

 been overlooked by ornithologists, at least since 

 1817. The names are Certhia longicauda, Tro- 

 chilus maximus, and Pipra tricolor, all of Karsten. 

 Viellot {Nouveau Dictionnaire d'Sistoire Natur- 

 elle, * * * Nouv. ed., T. VII. (1817), p. 364) re- 

 fers to Trochilus maximus giving the proper refer- 

 ence to Karsten' s work, but curiously enough 

 gives Latham as the authority for the -species. 



"While these names have not been noted in 

 recent works it seems they do not affect any 

 now in use in ornithologic nomenclature. This 

 statement is made on the authority of Mr. 

 Witmer Stone of this Academy. 



From a bibliographic standpoint it would be 

 interesting to know whether the Museum Leske- 

 anum Regnum Animale (1798) consists of one or 

 two volumes. Most bibliographers, to whom I 

 have referred, say two volumes ; but Cuvier {Le 

 Regne Animal, nouv. ed., T. III. (1830) gives 

 but one volume. In the library of the Acad- 

 emy of Natural Sciences of Philadelphia there 

 is volume I. only of the work, which is divided 

 into sis classes, viz. Mammalia, Aves, Am- 

 phibia, Pisces, Insecta, Vermes, the latter in- 

 cluding the invertebrates except the insects, 

 from which it will appear evident that nothing 

 remains of Animalia to be treated in another 

 volume. The first 44 pages (classes I. -IV.) of 

 the work are numbered in Roman, and parts 

 V. and VI. are numbered independently, and 

 are in Arabic (pp. 1-320). To this difference 

 in pagination may be due the statement that 

 the work is in two volumes. Or the fact that 

 Glasses V., Insecta (pp. 1-136), was published 

 in advance in 1788 with a separate title-page 

 may account for the other volume. 



William J. Fox. 

 Academy of Natural Sciences, Philadelphia. 



NOTES ON INOBGANIC CHEMISTBY. 



There has been a question frequently dis- 

 cussed as to the delicacy of spectroscopic reac- 

 tions as compared with the sense of smell. 

 Kirchhoff and Bunsen were able by the spectro- 

 scope to detect 1/14 X 10~'mg. of sodium ; on 

 the other hand, E. Fischer and Penzoldt could 

 recognize the odor of 1/460 X 10~^mg. of mer- 

 captan. It was clear, however, that the figures 

 of Bunsen by no means represented the limit, 

 and Professor F. Emich of the Technische Hoch- 

 schule of Graz has lately devoted some time to 

 the study of the problem. His results are pub- 

 lished in the Sitzungsberichte of the Academy 

 of Science of Vienna. His method is to use 

 Geissler tubes with exceedingly fine capillary 

 portion ; these are filled with hydrogen under 

 greatly diminished pressure. A slit at right 

 angles to the capillary allows the light from a 

 limited portion of substance to pass, the weight 

 of which is easily calculated. The lowest 

 pressure at which the line 3 is visible was ob- 

 served and from this the calculation made. 

 The results obtained in three observations were 

 1X10-'= mg., 7X10-»mg. and 3X10-"mg. 

 It thus appears that, on the average, the quan- 

 tity of hydrogen recognizable by the spectro- 

 scope is ten thousand times less than that of 

 mercaptan by the sense of smell. Emich calls 

 attention to the fact that if, as Hutton afiirms, 

 the ordinary hydrogen spectrum is visible only 

 when the gas contains a trace of oxygen, the 

 quantity of oxygen .thus detected by the spec- 

 troscope becomes far more minute than the 

 figures given for hydrogen. 



The subject of the radio-active substances in 

 pitchblende continues to excite the interest of 

 chemists, and much work is being done by the 

 two Curies, Giesel, Debierne, Becquerel, von 

 Lengyel and others. The last number of the 

 Chemical Neivs contains a paper by Bela von 

 Lengyel of Budapest, describing his eiForts to 

 prepare a radio-active barium synthetically. 

 His process is to fuse together uranyl nitrate 

 with two or three per cent, of barium nitrate, 

 and then fuse the oxides obtained in the elec- 

 tric arc. The fused mass is dissolved in nitric 

 acid, much of the barium nitrate crystallized 

 out, and the remainder of the barium precipi- 

 tated as the sulfate. The sulfate thus obtained 



