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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 8

 8 Wisconsin Academy of Sciences, Arts, and Letters 
the press, and much of this work has been done by myself. This statement
applies with especial force to Chapter IV, which attempts to give a limnological
application to the physical data found by Dr. James for lake waters. The
fullness of the data has permitted suggestions much more significant than
those which were drawn, in like manner, from the pioneer study of Dr. Pietenpol.
 Two matters in the Report call for special attention. The first relates
to the chapter on the action of distilled water on light. The tables and
diagrams which accompany Chapter II make it clear that much is still to be
learned about this part of the story. The wide differences between the percentile
curves, reported by observers from HUfner and Albrecht to Collins and Ganz,
are so great that they cannot be the result of accident or of instrument.
The percentile absorption found by Dr. James is by far the lowest among those
recorded in the short-wave spectrum; it agrees with that of the majority
about 5500 A; it. is among the highest at greater wave-lengths. Dr. James
tested many samples of distilled water; his readings were carefully made;
his results as stated are the mean of several concordant series. It was not
in the plan of the study to make an exhaustive investigation of distilled
water, in its relations to light, and of the variations which these present.
But the observations on filtered lake waters are in good general accord with
those on distilled water; they do not look toward the results reached by
other students where these depart most widely from those of Dr. James. It
would not be easy to give a reasonable interpretation to the observations
on filtered lake waters, if the action of distilled water were to be based,
for instance, on the curve of Sawyer, 4000-5000 A; or on those of Aschkinass
or Sawyer, 6000-7000 A. Lake waters and distilled water, as found by Dr.
James, seem to tell the same general story. But it is plain that new and
much more complete studies are needed on the relations of supposedly pure
water and light. 
 The second subject for special mention is that found in Chapter IV; the
analysis of the action of lake waters on light. The observations of Dr. James
were not made with the purpose of using them in such an analysis. The possibility
of this use was seen only after study had been directed to the great mass
of readings which Dr. James had made and had interpreted from the physicist's
point of view. A study specifically directed to- 

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