been applied in accordance with the experience of the United States Coast 

 and Geodetic Survey (see Appendix No. 7, Report for 1897-98, page 291). 

 ' The transit instrument used was of 3-inch aperture and 36-inch focal length, 

 with central illumination from the front of the objective, as described in the 

 Monthly Notices of the Royal Astronomical Society, Vol. 68, page 181, and 

 the method of observation was to reverse the instrument on every star. By 

 this means no correction for collimation was required. 



' For the first series of observations, the transit micrometer and a tape chronograph 

 were used, while, for the second series, the hand key and a Gautier printing 

 chronograph, made by the Societe Genevoise, were used. 



' Tests for personal equation were made on a transit of the sun on March 20th. 

 when Mr. Wright observed the first seven wires and Mr. Adams observed the 

 remaining eight wires : the instrument was then reversed and each observer 

 completed his observations on the wires previously used, the result being 

 that Mr. Wright observed 0-23 seconds later than Mr. Adams. 



" A complete example of the least square reduction of the observations taken on 

 March 5th is forwarded herewith. As will be seen from the schedule, column 7 

 gives the right ascension clock time of transit, corrected for level, clock rate, 

 diurnal aberration and half-width of contact strip of the transit micrometer. 

 Column 10 gives A, the azimuth correction. The headings of the other 

 columns explain their formation. 



" The clock correction is AT n = AT+<5T, where 



AT = mean of ^, 

 d = a 1,~ AT, 



the least square calculation gives a, the azimuth deviation from the meridian 

 in seconds of time, and ,\T the correction to AT in seconds of time. 

 " The right ascensions have been taken from the ' Nautical Almanac.' " 



