Experiments on the Alloys of Steel. 25 



nutes past six o'clock in the morning, which difference is to be 

 deducted thus : 



H. M. H. M. 



Morn. 9 51 Days 36530 



6 20 3 31 



3 31 36529 20 29 



Therefore from the New moon in April 1715 to the New moon 

 in May 1815, is 36529 days, 20 hours, 29 minutes. To find 

 the moon's motion from the sun, and the difference of their 

 motions for 100 solar years, proceed thus : 



Days. H. M. 

 Lunations completed in 36529 20 29 

 100 solar years .. 36524 5 40 



5 H 49 



In nineteen solar years are 235 lunations, and 5 x 1 9 = 95 years, 

 and 5x235 = 1175 lunations; and in five years odd days are 

 62 lunations, so that in 100 solar years are 1237 lunations, less 

 5 days, 14 hours, 49 minutes: the difference of the sun and 

 moon's motion in 100 years is therefore 5 days, 14 hours, 49 

 minutes, and this subtracted from one lunation gives the moon's 

 motion from tlie sun. 



To find the quantity of a mean lunation, divide 36529 days, 

 20 hours, 29 minutes, by 1237, the number of lunations, and 

 the quotient is 29 days, 12 hours, 44 minutes, 38 seconds, 51- 

 thirds, which is the precise mean quantity of a lunation, from 

 which subtract 5 days, 1 4 hours, 49 minutes, and the difference 

 18 the moon's motion required in the above period. 



D. H. M. S. T. 



One lunation 29 12 44 38 51 



5 14 49 



23 21 55 38 51 



Therefore in 100 solar years there are 1236 lunar months, 23 

 days, 21 hours, 55 minutes, 38 seconds, 51 thirds; and this cal- 

 culation is resolved on the principles of the weekly cycle. 



[To be continued.] 



Vol. 56. No. 267. Jw/?/ 1820. D - V. Erpe- 



