6l6 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



had set, and which were well developed, was counted. These were 

 marked so that the number that persisted until harvest could be 

 ascertained. 



Notes were also taken of the relative fioriferousness of the trees 

 and their relative fruitfulness when exposed to pollination by natural 

 means. These records are set out along with the experimental results 

 in Table II. 



Conditions of Experiment. 



The trees experimented with were all bush apples of fruiting age, 

 mostly on broad-leaved Paradise stocks, growing near the meteoro- 

 logical station on the hill at Wisley. The meteorological records thus 

 show well what the conditions to which the trees were exposed, during 

 the respective flowering periods, were. The reports on meteorological 

 observations at Wisley, already published,* will give particulars, and 

 the following Table summarizes the conditions over the whole flower- 

 ing period for each of the years considered. 



Table I. — The Meteorological Conditions at Wisley during the 

 Flowering Periods of Apples, 1911-1913. 





April 16-May 26, 



April 3-May 16, 



April 10-May 25, 





1911 



1912 



1913 



•f-Mean temperature of air at 9 a.m. 



54-9° 



52-6° 



50-3° 



Mean maximum temperature of 









air . 



61-7° 



60*2° 



58-5° 



Mean minimum temperature of air 



44-8° 



42-3° 



42-1° 



Mean minimum temperature on 









grass ..... 



38-6° 



32-9° 



38-3° 



Mean temperature of soil, i' down 



5i° 



5i-4° 



5 0-6° 



2 ' > 5 • 



5o-3° 



50-3° 



49-5° 



4' » • 



48-4° 



49-4° 



48-4° 



No. of ground frosts . 



7 



22 



9 



No. of air frosts 



0 



2 



2 



No. of minima below 42 0 



11 



22 



20 



Prevailing winds. 



s. & s.w.w. 



Winds very 



S. & s.w. 







variable 





Sunshine ..... 



257-4 



2976 



247'3 



Rainfall 



151 



061 



302 



Discussion of Results. 

 We do not propose to discuss the meaning of the results obtained 

 at this juncture, and the negative results especially are to be regarded 

 with great caution. So many factors interfere with fruit production, 

 besides the single one of lack of efficient pollination, that failure 



* Curtis, R. A., " On Meteorological Observations at WislejV Journal 

 R.U.S. vol. xxxviii., xxxix., and xl. 



f These particulars of temperatures give but a rough idea of the actual 

 temperatures to which the trees are exposed, although they are derived from 

 records made by instruments in the midst of the plantation. The very fact that 

 the first three are temperatures recorded within a Stevenson screen, while the 

 trees themselves are exposed, is sufficient to show this. Data have been collected 

 from the past four years by means of special instruments to show how the 

 exposure actually affects the matter. We hope to be in a position shortly to 

 give a summary of the records thus obtained and compare them with the screen 

 records. 



