1822.] the perpetual Renewal of Leases. 15 



If the tables of M. de Parceiux be used as given in Mr. 

 Baily's Annuities, take half the complement to 85 for 4 per cent, 

 and to 84' for 5 per cent. The following table will show how 

 near the true and approximate values agree : 



It will be observed that the half complements form arithme- 

 tical progressions whose common difference is half of unity. 

 The student must be careful not to mistake the half complement 

 for the expectation of the corresponding lives. 



