Magnotic Separations of Irou Lines iu Different Fields. 7 



component-; willi tlie ^^anio polarization were not measnred in 

 different tields. Tliungli the appearance of the components 

 belonging to the next order is troul)lesome in the measurement 

 of complex separations, it lias some advantage. Irregular 

 contraction of the gelatine film of a photograpliic plate may cause 

 some displacement of the silver deposit, and tiie error coming 

 from tliis may bo proportional to the separation, giving a large 

 errur for a strong tield. With echelon spectra we need not 

 mea-ure a separation larger than — ~—' but may simply add 

 ^he multiple of this quantity to the measured fraction, and can 

 tlius get an accurate vahie for the separation, provided that 

 Jy^^ is calculated witli sufficient accuracy. ^ 



Apparatus and Method of the Experinnent. 



The spai'k placed between the magnet poles was focused l)y a 

 lens on the horizontal slit s, of the echelon spectroscope, and the 

 image formed by the echelon was projected on the vertical slit So 

 of a Hilger constant deviation spectroscope Ijy means of a Eudolph's 

 planar of 5 cm. focus. The telescope of this spectroscope Avas 

 removed and its place was taken l:)y a }>hotographic camera with 

 an objective of 05 cm. focu-:. The rougli sketch is given in Fig. 1. 



Fio-. 1. 



C 



Oe 



I induction coil 



C I^eyJen jars 



L adjustable inductance 



S spark under examination 



S' anxjliary spark gap 



yi electromao-net 

 Si horizontal slit 

 E echelon irratin»- 

 A Kudclph's planar 

 W Wollaston prism 



?2 vertical slit 



K constant deviation prism 



P photographic camera 



