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Variation of Birds in a State of Nature by Frank Russell, 1892

Variation of Birds in a State of Nature by Frank Russell, 1892, Page 11

9

[illegible]

Note the opposite tendency of wing and tail, the correlation of length and wing, - a nearly constant factor.

In the next set of diagrams the relation of parts is shown by broken lines. Any correlation between the parts must be evident at a glance, as the lines will tend in the same direction, they will also show the variability of the parts in relation to the size of the bird i.e. where the proportions of parts are the most constant. The length is taken as the standard of measurement. But half the length is diagramed [illegible] to limited space. The smallest birds being taken first the line of course rises continually. A reference to the "second series" will show the no. and measurement of the specimen as those diagramed are marked there by a check mark [illegible] the length of the specimen. Each of the vertical lines represents a specimen, the horizontal lines are all absolute measurements of length from the base lines, so that not only is variation shown but also the actual length of parts. But [twenty?] specimens are here compared as the [illegible] of the other references and the careful selection of these from the fifty measured [sumed?] to render a greater number unnecessary.

 It will be [illegible] that the wing varies most in medium sized birds. The greatest variation of the tail is in those above the average. The [illegible] and

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9 [illegible] Note the opposite tendency of wing and tail, the correlation of length and wing, - a nearly constant factor. In the next set of diagrams the relation of parts is shown by broken lines. Any correlation between the parts must be evident at a glance, as the lines will tend in the same direction, they will also show the variability of the parts in relation to the size of the bird i.e. where the proportions of parts are the most constant. The length is taken as the standard of measurement. But half the length is diagramed [illegible] to limited space. The smallest birds being taken first the line of course rises continually. A reference to the "second series" will show the no. and measurement of the specimen as those diagramed are marked there by a check mark [illegible] the length of the specimen. Each of the vertical lines represents a specimen, the horizontal lines are all absolute measurements of length from the base lines, so that not only is variation shown but also the actual length of parts. But [twenty?] specimens are here compared as the [illegible] of the other references and the careful selection of these from the fifty measured [sumed?] to render a greater number unnecessary. It will be [illegible] that the wing varies most in medium sized birds. The greatest variation of the tail is in those above the average. The [illegible] and