The 1901 skirt (paper pattern) has less width round the bottom (without the flounce). Once the flounce is added, the skirt will have much more flare than the 1908.

The 1901 skirt also has darts which shape it much more round the hip.

The 1901 skirt is sometimes called a tulip or trumpet skirt, while the 1908 skirt is a circular skirt.

Here are the two patterns which I used for this comparison: the brown paper pattern is the Skirt Astarté, 1901. The plaid wool skirt is the 3-part skirt, 1908.