TIDES AND CUEKENTS IN BOSTON HARBOR 



63 



Table 26. — Summary of ranges and inequalities, Boston Navy Yard and Common- 

 wealth Pier No. 5 



Mean range 



Spring range 



Neap range - 



Perigean range 



Apogean range 



Great diurnal range -.- 



Small diurnal range 



Great tropic range 



Small tropic range... 



Average monthly extreme range 



Greatest range 



Diurnal high-water inequality 



Diurnal low-water inequality... r 



Spring tide level below mean tide level 

 Neap tide level above mean tide Ivel.. 

 Mean tide level below mean sea level.. 



For explanation of ranges and inequalities, see pp. 12, 17. 



Table 27. — Summary of tide planes, Boston Navy Yard and Commonwealth Pier 



No. 5 



Highest tide observed 



Average of monthly highest 



Perigean high water. 



Spring high water 



Mean higher high water 



Tropic higher high water... 



Mean high water 



Mean lower high water 



Apogean high water 



Neap high water 



Tropic lower high water 



Mean sea level... 



Sea-level datum.. 



Neap tide level 



Mean tide level 



Spring tide level 



Tropic higher low water 



Neap low water 



Apogean low water 



Mean higher low water 



Boston low-water datum... 



Mean low water 



Tropic lower low water 



Mean lower low water 



Spring low water... 



Perigean low water 



Average of monthly lowest- 

 Lowest tide observed 



Navy yard 



Referred 



;o sea-level 



datum 



Feet 



10.1 



6.89 



5.63 



6.45 



5.20 



5.15 



4.80 



4.40 



4.14 



4.14 



3.78 



.10 



.00 



-.02 



-.06 



-.10 



-4.07 



-4.18 



-4.25 



-4.58 



-4.87 



-4.91 



-5.09 



-5.24 



-5.64 



-5.74 



-7.04 



-8.4 



Referred 



to Boston 



low-water 



datum 



Feet 

 15.0 

 11.76 

 10.50 

 10.32 

 10.07 

 10.02 

 9.67 

 9.27 

 9.01 

 9.01 

 8.65 

 4.97 

 4.87 

 4.85 

 4.81 

 4.77 



.62 

 .29 

 .00 

 -.04 

 -.22 

 -.37 

 -.77 

 -.87 

 -2.17 

 -3.5 



Commonwealth Pier 

 No.S 



Referred 



to sea-level 



datum 



Referred 



to Boston 



low-water 



datum 



Feet 



7.8 



6.73 



5.47 



5.26 



5.03 



4.98 



4.58 



4.13 



3.91 



3.83 



3.67 



-.01 



.00 



-.08 I 



-.13 1 



-.19 ; 



-3.97 I 



-3. 99 I 



-4.06 



-4. 50 



-4.87 



-4. 84 I 



-4.95 i 



-5. 18 i 



-5.63 



-5.73 



-7.06 



-8.2 ; 



12.7 

 11.60 

 10.34 

 10.13 

 9.90 

 9.85 

 9.45 

 9.00 

 8.78 

 8.70 

 8.54 



81 

 37 

 00 

 03 

 08 

 31 

 76 

 86 

 2.19 



For explanation of tide planes, see p. 



