346 RESEARCH METHODS 



locating individual plants. Figure 125 shows the Hill panto- 

 graph with guide and division-plot tapes in use by the author. 



The instrument is provided with arms 40 inches long and set 

 to reduce to 3^, a reduction which, when it is applied to a 

 meter-square plot, makes a map scale of 10.5 inches on a side. 

 A substantial table about 20 inches square, mounted on a pivot 

 at one corner, supports the map and receives the impression. 

 The instrument is supported by a metal leg one inch high with a 

 ball roller, this being so attached to one arm that the arm swings 

 back and forth across the table when the instrument is in use. 

 Also, for the short tracing needle is substituted a steel needle 

 10 inches long for tracing the outHne or for locating the vege- 

 tation on the plot. 



The designer points out that a possible disadvantage in the 

 use of the pantograph is that the services of two persons are 

 necessary to chart successfully. One of these should be fa- 

 miliar with the flora and skilled in charting; the other records 

 the symbols of each species and handles the instrument. Any 

 disadvantage arising from two persons working together, how- 

 ever, appears to be offset by the increased accuracy and speed 

 secured. 



The advantages of locating the vegetation in position by 

 means of the pantograph are summarized by Hill as follows: 



1. The results are fully as accurate; the pantograph will record as accu- 

 rately as the skill of the operator in following the outline of plants will permit. 



2. The pantograph can be used with entire disregard of the presence of 

 rocks or impenetrable soil — factors very important in using straps. 



3. The rank growth of vegetation is even less of an obstacle to accuracy 

 with the pantograph than it is with the strap method, because the foliage can 

 readily be held with one hand while the outline of the plant is traced with the 

 other. WTiere straps are used the rank foliage is very apt to prevent the 

 straps from lying accurately in position. 



4. The work can be done more rapidly with the pantograph and with 

 much less tedium. (Two persons, only one of whom need be skilled, can chart 

 fully three times as many quadrats with the pantograph as one skilled person 

 can chart with straps.) 



5. The pantograph is especially efficient in locating individual seedlings or 

 one-stemmed plants and in tracing the outline of crowns of low bushes. 



