198 BULLETIN OF WISCONSIN NATURAL HISTORY SOCIETY. VcL. 2. NO. 4. 
River. A study of the movements of the bluebird north of St. 
Louis in the spring of 1885 show^s that there is a regular chrono- 
logical succession of data extending northward along the water 
courses (42). Another interesting feature is to be seen in the 
fact that those birds which followed the main highway reached 
higher latitudes in the same length of time than those which 
turned off to follow some tributary highway. It would thus seem 
evident that the birds reported from either side of the Mississippi 
River had been following it during some previous part of the jour- 
ney. A study of the records of a number of the other birds has 
shown results that are very similar. 
In connection with this work telescopic observations were be- 
gun at the Washburn Observatory at Madison, in the spring of 
1898, and were continued through 1899 and 1900. During the 
spring of 1900 interested persons from our western universities 
were asked to co-operate in the collection of data. The result was 
excellent. 
The following directions were sent to all who acknowledged 
their willingness to assist : 
BIRD MIGRATION. 
Directions for Observing with Telescope. 
The Instrument. 
Should be one with an objective ranging somewhere between 2 and 6 
inches. The eye-piece should be supplied with 2, or if possible 4, 
hair-lines crossing in the center, thus dividing the field of vision into 
quadrants or octants. 
Time of Observation. 
Begin to observe as soon as the moon is high enough to come distinctly 
into the field of vision, and continue until morning. 
To Begin the Observations. 
Focus the telescope on the moon with the point of intersection of the 
hair-lines on the moon's center. Turn the eye-piece so that one of the lines 
lies parallel to the direction in which the moon is moving across the 
heaven. Now turn to your note paper. At the head of this write the 
date, locality, direction of wind, and weather in general. Just below this 
draw a circle, putting in the hair-lines as they appear through the tele- 
scope. Number them, beginning at the right hand side of the one you 
have placed parallel to the direction of the moon and continuing counter 
clock-wise. See figure below: 
The Observations. 
(It is a difficult task to observe and write out the observations at the 
same time, and, also, it will tire the eyes to look at the bright moon too 
42. The movements of the bluebird are recorded in Cooke's Report on 
pages 293 and 294. 
