lii INTRODUCTION. 



Table 73. Time into arc. 



1^=15°; I'^^is'; 1^-15". 

 Example : 



Change 8'' 17™ 1^647 into arc. 



From the table, 8^ = 1 20° 



17'^ = 4 15' 



15" 



0.64 = 9.60 



By moving the decimal point, .007= o.io 



124° 15' 24'.'7 



Table 74. Days into decimals of a year and angle. 



The table gives for the beginning of each da}- the corresponding decimal 

 of the year to five places. Thus, at the epoch represented b}- the beginning 

 of the 15th day, the decimal of the year that has elapsed since January 10 



is computed from the fraction — -- — . The corresponding value in angle 



obtained by multiplying this fraction by 360°, is given to the nearest minute. 

 Two additional columns serve to enter the table with the day of the 

 month either of the common or the bissextile year as the argument, and 

 may be used also for converting the day of the month to the day of the 

 year, and vice versa. 



Example : 



To find the number of days and the decimal of a year between February 

 12 and August 27 in a bissextile year. 



Aug. 27 : Day of year = 240 ; decimal of a year = 0.65435 



Feb. 12: " " " 43; " " " =0.11499 



Interval in days = 197 ; interval in decimal of a year =0.53936 



The decimal of the year corresponding to the interval 197 days may 

 also be taken from the table by entering with the argument 198. 



Table 75. Hours, minutes a7id seconds into decimals of a day. 



The tabular values are given to six decimals. 

 Example: 



Convert 5^^ 24"^ 23?4 to the decimal of a day : 



5h ^ 0^208333 



24™ — 016667 



23^ = 266 



By interpolation, or by moving the decimal for 4^ 0.4 = 5 



0^225271 



