230 PROCEEDINGS OP THE AMERICAN ACADEMY 



tlirough the agenc}' of the larger "finder " of the great telescope. This 

 has an aperture of five iuohes, a power of thirty diameters, and a field 

 of view of seventy-eight minutes of arc. Two diagrams were usually 

 drawn in the book for each of these objects, — the one showing the 

 relation of adjacent objects in the great telescope, and the other the 

 configuration of the more conspicuous objects in the field of view of 

 the finder. Adjacent to these "finder" diagrams are the settings, — 

 to the nearest minute of arc in declination, and of time in right ascen- 

 sion,' — as read from the large finding-circles, divided in black and wliite. 

 The field of view of the finder is crossed by two pairs of hair-lines, 

 making a square of about twelve minutes on a side by their intersec- 

 tion at the centre. The diagrams in all cases represent the objects as 

 seen with an inverting eyepiece. As the adjustment of the finder was 

 occasionally verified, as well as the readings of the large circles, there 

 should be no trouble in identifying any of these objects, notwithstand- 

 ing the fact that no estimates of absolute magnitude were recorded. 

 The relative mngnitudes, while intended to be only approximate, are 

 still shown with sufficient accuracy for the purpose of the research, 

 and the diagrams are, in general, faithful tracings from the original 

 memoranda. 



I transcribe the observing-book entire. 



Telescopic search for trans-Neptunian planet, with 2Q>-inch equatorial. 



1877, Nov. 3.7. — Clamping polar axis, swept in declination, intend- 

 ing to detect planet by its supposed disk. Using power of 600, swept 

 along plane of orbit, from long. 155° to 166°. 



An object with slightly planetary look seen in a lO'' 27™, S-|-10° 0'. 



An object (nebulous and about 5" in diameter) found in a 11^ 9™. 5, 

 S -|-5° 28' : 



It follows a star a 44'.3 ; and precedes h 69' ; c 70^ 



Nov. 4.7. — Searching by same method, v, 148° — 163°. Power 



600. Soon clouded over. 



Nov. 6.7. — Attempted method of survey by recording R. A.'s of 



stars in narrow zones, estimating 8 and magnitude which were recorded 



by Townsend. Success not satisfactory — chronograph gave trouble. 



Then went on with sweep in declination, using power 400. v= 163° 



