1870.] The Solar Eclipse of August last. 31 



to keep this lens beyond the conjugate focus of the eye-lens, as 

 otherwise particles of dust on the former would have been too 

 faithfully portrayed by the latter. 



The elements actually adopted were as follows : — 



Ft. In. 



Focal length of objective 8 



375 

 687 

 6 

 375 



687 



2 



75 



62 



Kadius of field-lens 1 



„ eye-lens 0- 



Focus of field-lens 2- 



Diameter of field-lens (= E) 1 



Focus of eye-lens 1' 



Diameter of eye-lens ( = K) 0' 



Distance between lenses, 1-95 + 0-25 2 ■ 



Equivalent 1 



Distance of reticule from eye-lens for 5-in. distance"! , 



of ground glass J 



When the instruments were boxed and packed, it was found 

 that, with the various photographic appliances, they made no less 

 than live furniture-car loads of material. 



In arranging the division of the party into three sections, with 

 the three telescopes, so that they might be distributed along the 

 line of totality, and thus diminish the chance of universal extinction 

 by local clouds, Professor Morton was chiefly guided by the desire 

 of securing in each section such a diversity of special ability as might 

 make each self-dependent and complete ; also, to leave nothing 

 undone to secure content and harmony of feeling. He assigned to 

 himself the University telescope, which being of smaller size and 

 without clockwork movement, could not be expected to do as good 

 work as the others : though should they by chance be overclouded, 

 its result would be invaluable. 



The High School telescope, 6-inch aperture, 9 feet focal length, 

 was under the charge of Professor A. M. Mayer, Ph.D., and Mr. 

 O. H. Kendall. It was stationed at Burlington, 40° 48' 17" N., 

 Oh. 56m. 13s. West of Washington. By, measurements of the 

 photographs taken by this party, Professor Mayer has shown a 

 change of shape in one of the larger spots during the eclipse, 

 amounting to a motion of 2000 miles, in its edges. 



The Gettysburg telescope, 6-iDch aperture, 8-J feet focal length, 

 was in charge of Professor C. F. Himes, Mr. J. Zentmayer, and 

 Mr. E. Moelling. This was stationed at Ottumwa, about 75 miles 

 nearly west of Burlington. 



With the University telescopes were Mr. E. L. Wilson and 

 Professor Morton. This section was placed at Mount Pleasant, 

 between the other stations. 



It is almost needless to say that all officials connected with the 

 railways acted with the greatest liberality in transporting the appa- 

 ratus and observers to the selected sites. 



The various parties having reached their destinations, arrange- 

 ments were at once made to get the instruments into position. In 



