[ 259 J 
X. Preliminary Report on the Results obtained in Novaya Zernlya ivith the Prismatic 
Camera during the Ecligyse of the Sim, August 9th, 1896. 
By J. Norman Lockyer, C.B., F.R.S. 
Received November 17,—Read November 19, 1896. 
[Plate 9.] 
I STATE ill another communication the aiTangements made for obtaining results with 
prismatic cameras in Lapland, and how the attempts failed through bad weather. 
After the instruments had been dispatched to Lapland in H.M.S. “Volage,” Sir 
George Baden-Powell, K.C.M.G., M.P., generously, and with admirable public 
spirit, offered to take an expedition to Novaya Zendya in his yacht Otaria,” if 
observers and instruments were forthcoming. Sir George Baden-Powell consulted 
me on the subject, and ultimately, with the authority of the Vice-President of the 
Council, Mr. Shackleton, one of the computers employed by the Solar Physics 
Committee, was detailed to form part of the expedition, 
Tlie prismatic camera available was that which had been used in Brazil during the 
solar eclipse of 1893. The object glass is a Dallmeyer doublet of 19 inches equiva¬ 
lent focal length, with an aperture of 3’25 inches ; the image of the inner corona, 
therefore, is a ring of 0'2 inch diameter. Two prisms of 3 inches clear aperture were 
used, with their refracting edges perpendicular to the horizontal, each having a 
refractive angle of 60°, the light being reflected into the apparatus by a siderostat. 
The length of the spectrum given by this combination was 1'5 inches, from F to K, 
or 2‘3 inches, from Dg to K. 
In 1893, the photographs obtained by this instrument in Brazil were not in focus 
in the ultra-violet, in consequence of the difficulties of adjustment under eclipse con¬ 
ditions. The precaution was taken, therefore, of making all the necessaiy adjustments 
by obtaining some stellar photographs with the instrument before it left England. 
Ultimately, a photograph of a Lyrse left nothing to he desired, and the then positions 
of all the parts were carefully marked. 
Three specially-constructed dark slides, carrying eight plates each (4^ X If inches), 
were employed, the change from plate to plate being effected by means of a rack and 
pinion attached to the dark slides. The plates used were Edwards’ isochromatic. 
The following table, based on data fui'nished by the results of the 1893 eclipse, 
2 L 2 26.7.97 
