Water changed repeatedly 569 



circulation (see also circulation) 49, 133, 185, 719, 995, 996, 2077 



, clean 240, 643, 1016, 1522 



cleaned up 645 



, clear 369, 657 



, cold 40, 337 



, concentration of aquarium 635 



condition, widespread 432 



conditions, static 391 



content 99, 2209 



of sediments 780 



, control of 168 



currents 150, 391, 575, 654, 1123 



, differential 276 



, deep 250, 1418 

 , deepest 651 



depth (see also depth of burial) 76, 123, 266, 679, 691, 1219, 1604, 2084 

 r diluting 15, 1310 

 , distilled 193 

 , ejection of 101 

 , enhancement of 16 8 

 , examination of intake 16 8 

 , excess 85 

 , extreme low 651, 1244 

 , filter 944 

 , filtered bay 272 

 , sea 475 



flow 816 



, low summer 828 



, minimum 24 8 



, fresh 211, 1418, 2047 

 , heated 639, 1926 



heating system 1197 



jet, confines and directs 1022 



, strengthens 1022 



, just below low 899 

 , large volumes of 417 



layer, turbid 1540 



leaving exhalent siphon 629 

 , low 152, 425 

 , minced clam wash 86 5 



movement 65, 1163, 2077 



permeability 1515 



pollution 317, 467, 530, 549, 694, 933, 1177, 1213, 1216, 1251, 1299, 1301, 



1410, 1602, 1656, 1859, 1869 



a serious problem in Mass., R. I . t and N. Y. 1811 



control 902 



839 



