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MEUS MNENTE MERERI EN UD 
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(724) 
Visual characteristics of objects, especially vegetation or individual trees 
which can be used in deriving diagnostic keys. 
Intrinsic Characteristics. 
Relative Tone or Density, a device for providing light for the difference in 
tone as registered on light, medium or dark prints. 
Texture on a scale of 1/1000 approximately 
Texture on a scale of 1/4000 
Texture on a scale of 1/16,000 
Texture on a scale of 1/64,000 
Pattern e.g. concentric zonation. 
Usual color at any given season for any given species. 
Usual color of usual background at this season. 
Shape (accurately described) by comparison with plates such as in Linne’s 
Philosophia Botanica and Bischof’s definitions and plates in “Termi- 
nologie”. 
Size (by well-known methods). 
Season when most distinct from its background. 
System of photography giving greatest contrast for any given season (This 
includes type of film, kind of filter, etc.) 
»” 
33 
39 
Extrinsic Characteristics. 
Place in commonest succession of plant societies. 
Effect of competition on distribution and habitat. 
Effect of topography or geomorphology. 
Effect of water table. 
Effect of wind, frost, dew and other weather conditions. 
Effect of climate. 
Characteristics revealed by special instrumentation. 
Quantity per unit area. (by means of Robertson's *Moosehorn" exhibited here 
and similar methods for obtaining quantitative data) 
Stereoptican effect or exaggerated effect. 
In order that a table such as the foregoing, and any keys derived from it, 
should function accurately, it is necessary that a precise terminology be accu- 
rately defined and that a set of standards upon which this terminology is based, 
be adopted. The Bureau of Standards has provided us with many sets of stand- 
ards which can very advantageously be adopted bodily here. The author plans 
to publish soon a precise terminology of such characters as texture, shape, 
pattern and their use in keys for photo-interpretation. It is planned to do this 
without inventing a single new technical term and to use only the best under- 
stood terms used by the most people without doing violence to the English 
language. 
In this same article, a mechanical procedure for making diagnostic keys as 
fool-proof as possible will be described. The time is too short to say more than 
this here. 
My sincerest thanks are due Lt. Commander Robert Colwell, President of 
Commission VII, for his kind assistance in arranging for the presentation of 
this paper and the exhibition of the three inventions by Mr. Nagel and myself 
at last Thursday's meeting. 
   
  
  
   
  
  
  
   
  
  
  
  
   
   
    
  
    
   
  
  
  
  
    
    
    
   
     
   
    
   
    
  
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