H. A. Newton— Fireball of January 13th, 1893. 169 



Danbury north 3"-6 or about 370 feet. The line for 7 h 30 m 

 crosses centrally the upper Kohanza reservoir as given upon 

 the Danbnry sheet of the new map of Connecticut. The 

 plane was at 7 h 33 m inclined 10° 3 / to the vertical at Ansonia, 

 and the earth's rotation in five minutes would change this 

 inclination by a very small quantity, a quantity, however, so 

 small that it may be safely neglected. 



30. The various observations reported in 4-25 when used 

 for computing the meteor's path through the air are of neces- 

 sity liable to large errors. This is almost universally true for 

 such meteors. The proper adjustment of the unavoidable dis- 

 crepancies is a matter of some delicacy. No systematic treat- 

 ment like the method of least squares is feasible. ISTo formal 

 system of balancing the errors, or taking an average seems 

 proper. The difficulties that arise are not those wnich a mere 

 computer meets with, but are much more like those which a 

 judge encounters when the witnesses give conflicting stories. 

 The judge hears the evidence of all the parties, and then tak- 

 ing into account the way in which witnesses are accustomed to 

 use language, and all the necessary and all the probable rela- 

 tions of the parties and things concerned, works out of conflict- 

 ing stories what to his mind is the most reasonable statement 

 of the facts. 



31. If a meteor's path through the air is regarded as part of 

 a straight line the location of that line is evidently determined 

 by four conditions ; or, if the beginning and ending of the 

 body's path are to be found, two more conditions, six in all, are 

 to be fulfilled. Each usable observation taken by itself gives 

 one or more equations and reduces by one, or more than one, 

 the number of remaining conditions. When, however, the 

 observations furnish more equations of condition than the 

 four or six required an adjustment becomes necessary. 



In practice I have found it better in collating meteor obser- 

 vations to first select the best observations and use these 

 exactly as made to reduce the number of unknowns to be 

 found. In the present case the photographed track is of 

 course the best observation, and it furnishes two out of the 

 four conditions needed to fix the line of the meteor's motion. 

 The photograph determines a plane through Ansonia and the 

 required line. Relative to the stars the plane is quite exactly 

 determined, the errors being principally such as are caused by 

 errors of the measurements which I made on Mr. Lewis's 

 original slide. The probable error of one measurement I esti- 

 mated at about three-tenths of a minute of arc. The relation 

 of this plane to the earth's surface, and so to other observers 

 is however further affected as shown above (29) by the uncer- 



