50^ Report Brit: Assoc- 1880. 



Plate K. 



DECLINATION 



Mat'ck 28-29 1879. 



<SP Petersburg 



Hon. 



Force at Hew. 



Verii. Forde, at' Hew. 



oroe, I 



4-ay.nh. 



UJUistroduijg Professor W. GryU^s Adanvs' (hmmutucatwrL: 



Contpor'isorv of Curves of the BecUn/jijbcn,' Maqnelographs at Kew, 

 Stcio/hurst, CounhrcUjLtshotv, Vie-ruui/, and St" Pctej^sburg.' 



