Visibility . Cisco records: visibility is given in 

 descriptive terms (table 1). Williams records: 

 coded as indicated in table 16. 



Sea . Cisco records: the approximate amounts 

 of swell and/or waves are given in descriptive 

 terms; calm, gentle,"', (table 1). Williams 

 records: coded as indicated in table 16. 



Secch i disc . The maximum depth at which the 

 Secchi disc was visible is recorded in meters. 

 Actual measurements were made with a chain 

 calibrated in feet. 



Bottom. The bottom type as determined from 

 dredge samples is recorded in descriptive terms; 

 silt, mud, clay, sand, gravel, and rock. 



Sodium . Values are in parts per million to 

 nearest 0. 05. 



Silica . Values are to the nearest part per mil- 

 lion. 



Dissolved nitrogen . These values are for am- 

 monia nitrogen, given as parts per million to 

 two decimal places. 



Tota l phosphorous. Values are recorded to the 

 nearest part per billion. Tr means trace. 



Biological 



Procedures for determination of the following 

 categories are given under the explanation of data. 



Bathythermograph number. Bathythermograph 

 tracings were numbered consecutive ly (arable 

 numerals) starting with one at the beginning of 

 each cruise of the Cisco. They were numbered 

 consecutively from the first of the operating 

 season on the Williams . 



Temperature . All temperatures are Centigrade 

 and recorded to the nearest 0. 1*. 



Chemical 



pH . Hydrogen- ion concentration expressed as 

 pH values to one decimal place. 



Specific conductance . Specific conductance is 

 given in mhos/cm x 10^ at 18* C. (K-^^ x 10^). 



Dissolved oxygen . Values are in parts per mil- 

 lion to one decimal place. 



Total alkalinity . Values are in parts per mil- 

 lion to one decimal place, in terms of calcium 

 carbonate. 



Calcium . Values are in parts per million to 

 one decimal place. 



Magnesium. Values are in parts pet million 

 to one decimal place. 



Wet volume . The wet volume of plankton is 

 given in milliliters per cubic meter to three 

 decimal places. Large organisms occurred in 

 the samples only occasionally so that the vol- 

 umes represent smaller organisms. 



Dry weigh t. The dry weight of plankton is given 

 in milligrams per cubic meter. 



Ash content . Weight of the sample after the or- 

 ganic content has been burned; given in milli- 

 grams per cubic meter. 



Organic content. Difference between dry weight 

 and ash weight; given in milligrams per cubic 

 meter. 



LITERATURE CITED 



American Public Health Association 



1946. Standard methods for die examination 

 of water and sewage. 9th ed. , 286 pp. 



Ellis, M. M. , B. A. Westfall, and Marion D. Ellis 

 1948. Determination of water quality. U. S. 

 Fish and Wildlife Serv. Res. Rept. 9, 

 122 pp. 



Fry, F.E.J. 



1956. Movements of drift cards in Georgian 



Bay in 1953. Jour. Fish. Res. Bd. Can, , 

 vol. 13, pp. 1-5. 



23 



