J 



- 12 - 



ill 



r - — • (1) 



It is possible to assign J^ unit value and express J as its 

 multiple. Thus the time scale in a model compressing the events 

 of one mean solar day within the ccmpass of one mean solar min- 

 ute; Tj, = T^/Tp = 1/1440. The units of the ratio cancel mathe- 

 matically but if they are preserved the scaling ratio expresses, 

 instance for instance, the proportion in common units of the 

 homologous quantity in either the model or the prototype. In 

 the case illustrated one may justly speak and think interpreta- 

 tively of a model "day" but this interval is still only one mean 

 solar minute for purposes of calculation. 



Choice of the vertical and horizontal scales was determined 

 for the Barataria Bay model by the dimensions of the available 

 space, the vertical distortion required to maintain a useful 

 depth of water and by the rate of going of the model. Because 

 of the complexity of the water-land areas in the Barataria Bay 

 region it was considered imprudent to build the model on a hori- 

 zontal scale smaUer than 1/20,000. Ihis horizontal scale allows 

 all the area of interest to the sponsors and the additional areas 

 containing significant influences of oceanographic and hydrologic 

 kinds, except part of Little Lake, to be included in a space 

 eight by eight feet. The remainder of Little Lake was represented 

 by a box of equivalent area mounted on the outside of the model at 



