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Durand, Loyal, Jr. (ed.) / Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume XXXI (1938)

James, Harry Raymond; Birge, Edward A.
A laboratory study of the absorption of light by lake waters,   pp. [1]-154 PDF (46.6 MB)

Page 152

 152 Wisconsin Academy of Sciences, Arts, and Letters 
 3. Percentile absorption, as determined for the present re 
port, is compared with that found in Wisconsin lakes by Pietenpol some 15
years earlier. The general character of the lake waters and of their action
on light seems to be fairly constant. Comparison is also made with determinations
made on German lakes by von Aufsess and on a Minnesota lake by Erikson. Their
results can be interpreted by the results from the larger series of Wisconsin
Section 4. Figs. 19-28; pp. 78-98 
 1. This section contains 8 diagrams, Figs. 19-26, which illusstrate the
effect of settling, filtering, and dilution on light absorption by the waters
of individual lakes. They show the behavior of the waters from the three
Groups defined above, when subjected to these treatments. This behavior is
discussed for each diagram. 
 2. Figs. 27, 28 contain absorption curves for settled or fil 
tered lake waters whose effect on light was read to 3650 A. They show the
same characteristics as do those for the smaller spectral range, but in a
more extreme form. 
 1. In this chapter there is attempted an elementary analysis 
of the action of lake waters on light. The total effect of a water is divided
between two or more factors; and approximate quantitative values are assigned
to them. Three methods are presented of such distribution of total action;
each yields curves of a different type; the results are given in diagrams
rather than in numerical tables. In all cases the unit for the action of
water is a stratum one meter in thickness. 
 2. The ordinates for remainder curves are derived from those for a percentile
absorption curve by subtracting the absorption ordinates of pure water. The
resulting curve shows a relatively high percentile absorption in the short-wave
spectrum, its amount depending primarily on the color of the water. Absorption
becomes less in the long-wave spectrum and is small or negligible, 7400-8000
A. Remainder curves also show for any lake water the percentile absorption
which is added to that of water by all other factors combined. In this computation

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