136 
Figure 8 is a histogram of the information contained in Table 4. 
The contribution of each type of data source is shown by percentage 
frequency distribution. The open portion of each bar indicates the 
percentage of usable sources, and the shaded portions indicate the 
percentages of unusable and "no contact" sources. 
Figure 9, also a histogram, summarizes the percentage of usable, 
unusable, and no contact sources for (1) the onshore sources, (2) the 
inland sources, ana (3) the total sources for the entire drainage basin. 
A bibliography is appended to this report which gives references 
on the subjects of hydrography and meteorology as they pertain to 
potentially applicable scientific problems of the Great Lakes. 
