On page 85 and 86, Vol. 13, No. 1, September 20, 1929, the cuts for Figs. 10 and 11 should be interchanged. The cut on page 85 is Fig. 11 and should appear on page 86. The cut on page 86 is Fig. 10 and should appear on page 85. The legends should remain on the pages where they now appear.

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