of the Bessemer -flame. 83 



curve; and although the curves obtained vary slightly in degree 

 of curvature, they yield concordant results. 



The following determinations of the wave-lengths of two of 

 the brightest lines will show about the degree of accuracy attain- 

 able : — 



Reference-spectrum. Bessemer-spectrum. 

 Wave-length. Reading. Reading. w Je-len<Hh. 



Air . . 



. 5678 



11-33 



13-18 



5580 



Air . . 



. 5534 



14-09 



1773 



5359 



Copper . 



. 5292 



19-24 







Copper . 



. 5217 



2100 







Lead 



. 5607 



9-77 



10-28 



5580 



Lead 



. 5372 



14-55 













14-84 



5358 



Air . . 



. 5495 



12-21 







Lead . 



. 5372 



14-63 







14-89 



5360 



Lead . 



5045 



22-50 



Cadmium . 5378 14-38 



14-81 5358 

 Cadmium . 5337 15-27 



The following measurements of the same two lines were made 

 with the micrometer eyepiece : — 



Reference-spectrum. Bessemer-spectrum. 



Wave-length. Reading. Reading. wave e _fength . 

 Tin . . . 5563 O'lO 



1-55 5580 

 Tin . . . 5588 2-20 



