102 



Pearl and Surface. 



uuinber of zero frequencies. This arises from the fact that the range 

 of the observations is much greater towards the middle of the growing 

 season. Considering the data as a whole it appears that no uniform 

 grouping could be obtained which would give better distributions. 



From these distributions the means, standard deviations and 

 coefficients of variabilitj- have been calculated. These together with 

 their probable errors are given in tables 1 to 6'). 



Table 1. 

 Constants of Variation in Height of Plants for Series A. 



Date of Measurement 



Mean 



Standard Deviation 



Coefficient of 

 Variation 



June 12 

 June 15 

 June 19 

 June 22 

 June 26 

 June 2!) 

 July 3 

 July 6 

 July 10 

 July la 

 July 17 

 July 20 

 July 24 

 July 27 



1.39 



189 



228 



299 



3.S1 



385 



441 



554 



689 



824 



974 



1103 



1193 



1215 



2-32 

 :3-49 



4-74 

 ;4-79 

 :4-65 

 :4-08 

 .6-06 



7-20 

 ;9-66 

 : 12-15 



12-18 

 .11-07 



9-71 



9-36 



25-28 



38-07 



51-61 



52-14 



50-62 



44-49 



66-06 



78-48 



105-19 



132-42 



132-68 



120-57 



105-81 



10200 



±1-64 

 + 2-47 

 ±3-35 

 ±3-38 

 ±3-29 

 ±2-89 

 ±4-29 

 ±5-09 

 ±6-83 

 ±8-59 

 ±8-61 

 ±7-83 

 ±6-87 

 + 6-62 



18-14 ±1-21 

 20-10 ± 1-36 

 22-61 ± 1-55 

 17-44 ±1-17 

 15-27 ± 1-01 

 11-55 ±0-76 

 14-96 - 0-99 

 14-15 ± 0-94 

 15-25 ± 1-01 

 16-07 ±1-07 

 12-62 ± 0-83 

 10-93 ±0-72 

 8-87 ± 0-58 

 8-39 _+ 0-55 



') It will be noted from the tables that the measurements of the different series 

 were not all made on the same day. Since it was not convenient to devote all of any 

 one day to making tliese measurements, the convention was adopted of measuring only 

 one set of plants on any half day. Thus the first measurements on Series B were made 

 on the afternoon of June 11. Series A was measured on the forenoon of June 12 and 

 Series C on the afternoon of the same day. The next measuiement of Series B was on 

 the forenoon of June 15, Series A on the afternoon of that day and Series C on the 

 forenoon of June 16. In this way the interval between tlie measurements of each series 

 was three and one-half days. For convenience in plotting, the dates of measurements 

 have been grouped and supposed to center on one of these days. Thus in figures 1 to 3 

 the first measurements are plotted as if all were made on .Tune 12, the second on June 15 

 and so on. This will serve to explain any apparent discrepancy between the tables and 

 the figures. 



