On the Lines in the Spectra of some of the Fixed Stars. 319 



that its true position is by the side of mercury, lead, or silver. The 

 ready dehydration of its basic oxide; the insolubility of its sulphide, 

 iodide, chloride, bromide, chromate, phosphate, sulphocyanide, and 

 ferrocyanide ; its great atomic weight ; its ready reduction by zinc 

 to the metallic state ; its power of forming a strongly acid oxide ; 

 and, according to Dr. Miller, the complexity of its photographic 

 spectrum, — all prove that thallium cannot consistently be classed 

 anywhere but amongst the heavy metals, mercury, silver, lead, &c. 

 No weight is attached to M. Dumas' s argument in favour of thallium 

 being related to potassium and sodium because its equivalent is 

 rather near a figure obtained by adding twice the atomic weight 

 of one metal to four times the atomic weight of the other. The 

 author shows that, by similar processes of addition, multiplication, 

 or subtraction, it is not difficult to prove that thallium is related 

 to any desired group of elements. 



The author gives full analytical notes on thallium, showing where 

 it would occur in the ordinary course of analysis, and detailing 

 accurate methods of separating it from every metal with which it 

 can be accompanied. 



February 26. — Major- General Sabine, President, in the Chair. 



The following communications were read: — 



"On the effect of Temperature on the Secretion of Urea, as 

 observed on a Voyage to China, and at Hong Kong," By Emil 

 Becher, M.D. 



"On Clinant Geometry, as a means of expressing the General 

 Relations of Points in a Plane, realizing Imaginaries, reconciling 

 Ordinary Algebra with Plane Geometry, and extending the Theories 

 of Anharmonic Ratios." By Alexander J. Ellis, B.A., F.C.P.S. 



"Note on the Lines in the Spectra of some of the Fixed Stars." 

 By William Huggins, Esq., F.R.A.S., and William Allen Miller, 

 M.D., LL.D., Treasurer and V.P.R.S. 



The recent detailed examination of the solar spectrum, and the 

 remarkable observations of Kirchhoff upon the connexion of the 

 dark lines of Fraunhofer with the bright lines of artificial flames, 

 having imparted new interest to the investigation of spectra, it has 

 appeared to the authors of the present note that the Royal Society 

 may not consider a brief account of their recent inquiry upon the 

 spectra of some of the self-luminous bodies of the heavens unworthy 

 of attention, although the investigation is as yet far from complete. 



After devoting considerable time to the construction of apparatus 

 suitable to this delicate branch of inquiry, they have at length 

 succeeded in contriving an arrangement which has enabled them 

 to view the lines in the stellar spectra in much greater detail than 

 has been figured or described by any previous observer. The 

 apparatus also permits of the immediate comparison of the stellar 

 spectra with those of terrestrial flames. The accompanying drawing 

 shows with considerable accuracy the principal lines which the 



