386 Mr. Baly and Dr. Syers on 



are known to be functions o£ the magnetic field, and the 

 effect of the field upon their three space-components is well 

 known. 



The constants Ci, C 2v . .C m determine the relative intensities 

 of the maxima but not their form or position, since they do 

 not occur in the derivatives of the function. Both the position 

 and the form of the finite maxima depend on the values of B 

 and n, and the latter at least depends upon the distribution of 

 the ionic or molecular periods about the mean. Both these 

 parameters appear to be a minimum for perfect radiators. 

 B and perhaps n also are functions of the pressure when this 

 is variable. 



It is hoped that this rather desultory discussion of the 

 critical properties of the complete emission function may prove 

 useful and suggestive in the further investigation of the 

 emission of partial radiators. It may be indicative of the 

 possible great practical value of the discussion of physical 

 functions from the standpoint and by the methods of modern 

 mathematical function theory. The results obtained are of 

 course only tentative at best, and liable to be greatly modified 

 by new experimental evidence, yet the same may be said of 

 elaborate analytical deductions. 



Berkeley, California, 

 April 1901. 



XXXIX. The Spectrum of Cyanogen. 

 By E. C. C. Baly, F.I.C., and H. W. Syers, M.A.,M.D* 



IN a recent paper in the Philosophical Magazine on the 

 Spectra of Carbon f , Professor Smithells pointed out 

 the desirability of observing the vacuum-tube spectrum of 

 cyanogen, with particular reference to the presence or absence 

 of the spectra of carbon, inasmuch as their absence would 

 materially support the explanation he puts forward as to their 

 origin, namely, that the carbon-oxide spectrum is due to 

 carbon dioxide, and the Swan spectrum to carbon monoxide, 

 while the line spectrum is due to the element carbon. 



One of us in a previous paper J, some years back, in dealing 

 with the stratification of the electric discharge, described 

 experiments which had been made on mixtures of hydrogen 

 and carbon dioxide and referred to the spectra seen as those 

 of hydrogen and carbon dioxide. This has since been criticised 



* Communicated by the Physical Society : read June 28, 1901. 



t Phil. Mag. April 1901. 



| Baly, Phil. Mag. xxxv. p. 200 (1893). 



