56 



MICHIGAN ACADEMY OF SCIENCE. 



Combining all the stars used for flexure we find 



Clamp West , 

 Clamp East . . 



A* 



40.51 ' 

 —0.38 



The flexure as found represents the combined ett'eet on the circle and 

 telescope, which as yet has not been separated into the two parts. Such 

 a term as 1)^ in the flexure of the telescope proper would be caused, I 

 suppose, by the axis of symmetrj^ of the telescope not coinciding with 

 the neutral axis. 



As has been stated the value of *. was assumed +48° 16' 49.3", and a* 

 is the correction to be added to this. In order to check the value of a*^ 

 I have assumed the values a^ = + 1.20", &, =:-1.46", and have used only 

 stars near the zenith for computing this ciuantity, with the following 

 results: 



Clamp East— South stars a <|> = 53" 

 North stars — 0-85 



Clamp West— South stars 

 North stars 



Mean 



-0.31 

 -0.66 



-0.58 



For the present, the latitude can be assumed 



+42° 16' 48.8". 



Situated as we are, an elaborate determination of the division errors 

 cannot be made, so that it will be necessary to secure more values of the 

 latitude, turning the circle on its axis, and observing direct and reflected, 

 and clamp east and west. From my experience with large, heavy instru- 

 ments I do not believe much in the application of such corrections as those 

 of flexure and division error, but think that observations should be ar- 

 ranged as far as possible so as to eliminate all such quantities. 



The flexure seems to be rather constant. Before beginning observations 

 of Polaris, I had the foreman of the University engineering shops ex- 

 amine the screws which hold the telescope cones to the cube. It was his 

 opinion that I had driven them up too tight, and, therefore, they were 

 loosened a trifle. 



13. — Meteorological Instruments. 



The standard barometer was examined at Ann Arbor by Professor 

 Marvin of the Weather Bureau Oflice in the summer of 1892. It was 

 found to be badly out of order, and in trying to make repairs the glass 

 tube was broken. The instrument was then taken to tlie Weather Bureau 

 OflSce in Washington, and a new 1ul)e was filled and inserted. Also, a 

 new attiu-hed llicniiometer was ]»ut on, since the old one was found 1° 

 in error. 



Our thermometers, also, have been examined by the Weather Bureau 

 and I have to thank the officials in Washington and Lansing for the con- 

 siderable attention wliicli tliey liavc ]>aid 1o our meteorological instru- 

 ments. 



