Before we get into the theory, however, indulge with me in a little thought experiment. (Gedanken)
Imagine I have a database of randomly occurring measurements (for instance I just happen to have a database of the altitude of the top 122,000 populated towns in the World).
If I were to plot a frequency histogram of this data based on the leftmost digit of each altitude (in feet), what do you think the shape of the graph would be?