THE BAHAMA ISLAKDS 93 



which, by means of Table 22, Appendix 7, Coast and Geodetic Survey Eeport 



for 1894, becomes 



Mn = 2.04 M, x Table 22 + .035 M^ (v — w) sin {-iMl — Ml) 



+ M, (cos V + cos w) + 2M, cos {3MI — M% — %M^ (12) 



in which the v and w are the same as obtained for (1) and (2). By (12) the 

 mean range of tide at Nassau from the harmonic constants is 



ifM= 2.609 ft. 

 and from the high and low waters this range was found to be 



Mn=L'l.<o2,\ ft. 



The spring and neap ranges of tide may be obtained from the harmonic 

 constants by the formulas 



^, = ^«-.536^+[l.96_.08(^'J] 



X IS, + At, cos {%M\ -S\- /.§)] (13) 



N, = Mn- .536 ^ - [l.96 - .08 (^^ J] 



X IS, + /., cos (2ilf« -S\- /4)J (U) 



in: which the first and last letters of the words spring and neap are used as 



abbreviations. 



From (13) and (14) we obtain 



8g = 3.051 ft., and 'Nf — 2.129 ft. 



The heights of the tropic tides may be found by the following formulas : 



Tropic HH'W = 1.02 A, X Table 45, above MSL .(15) 



" LHW= " " " " (16) 



" HLW= " " " " (17) 



" LLW= " " " " (18) 



where Aa = 1-010 M, + 0.27-^-^2 cos [(iT? - (9?) ~ {Kl - if §)], 



and the table is in Appendix 9 of the Coast and Geodetic Survey Eeport for 

 1897, different arguments being used for entering the table for the various 

 tides. Prom (15), (16), (17), and (18), we find 



Tropic HHW — 1.737 ft. above mean sea level. 

 Z^IF= 0.735 " " " " " 

 HLW= 1.124: " below " " " 



" LLW=l.i:04: " " " " " 



The difference between the two high waters of the tropic tides is called the 

 tropic high water diurnal inequality, abbreviated to. Tropic HWQ, and the 



