312 Mr. G. A. Hemsalech on the Luminous Vapours 

 § 8. Manganese. 



Two pieces of the metal were laid upon the graphite plate 

 as shown in fig. 2, and photographic observations made both 

 with a protecting layer of pure carborundum and without. 

 The tabulated results are based on an experiment made with 

 an unprotected plate raised to a temperature of about 



3000° C; the acting electric field was about 8 ^- s . The 



' & cms. 



relative intensities for the lines in the luminous vapour refer 

 to the region situated just below the fringe, where the 

 temperature will be slightly less than on the surface of 

 the plate. No detailed results concerning the air-coal gas 

 flame spectrum of this element are as yet available, but 

 Dr. de Watteville very kindly placed at my disposal copies 

 of his original photographs of this spectrum, from which 

 I was able to derive the relative intensities of the manganese 

 lines in cone and mantle. These results as well as the 

 relative intensities in arc and spark for the lines of the same 

 element according to Messrs. Exner and Haschek have been 

 added for comparison. 





Single plate furnace. 



Air-coal gas flame. 











Luminous 







>i 







Fringe 



Vapour 







Mantle 







X. 



(thermo- 



(therino- 





Cone 



(therm o- 







electrical 



chemical 



Type. 



(chemical 



chemical 



Arc. 



Spar 





excitation). 



excitation 

 at 2900° 0.). 





excitation). 



excitation 

 at 1850° C). 







4018-09 



2 



1 



tadpole 



2 







10 



8 



4030-80 



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long 



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10 



100 



20 



4033-08 



8 



8 





10 



10 



100 



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4034-48 



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8 



8 



50 



10 



4035-73 



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4041-34 



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long? 



4 



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4055-55 



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short? 



observation impeded 



3 



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4265-92 







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00 



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long 



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5394-68 



2 



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5432-55 



1 



s 



5 



.; 



4 



4 







