tapped on each da)'. Making .'in allowance for days on which by 

 reason of stress of weather, festivals, or other circumstances no 

 tapping is possible, this fraction may be taken as equivalent 



tO 12%. 



This may of course be divided into two lots of 6% for morning 

 and evening tappings. 



Whether each individual tree be reopened on each successive day 

 or on alternate days will not affect these results, it would mean 

 that different sets of trees would be worked on alternate days but 

 each set would comprise 12% of the total trees. 



The division of the trees into groups tor morning and evening 

 tapping will make it advisable to cut the central channel for the 

 morning group on the South side of the trunk, that for the evening 

 tapping on the N.orth side of the tree so as to avoid the coagulation 



of the latex in the cuts by the influence of sunshine. 



The preceding calculation can be put in general terms and a 

 formula given thus. 



Let W be the width of the first cut. 



— w be the thickness removed by each subsequent cut. 



— T be the interval of rest between successive tappings, 



measured in years. 



— t be the number of times each cut is reopened. 



— D be the days per annum when tapping is impossible. 

 Then the spaces to be left between the lateral branches of the 



. . . tw + W 

 herring bone are jj 



T , et , , 100 1 + 100 



Ine percentage ot trees tapped daily 335 f _ 



The thicknesses are measured vertically in inches. By stating 

 the matter in this condensed form the nature of the inconstan : 

 quantities is clearly realised. 



Thus W the w idth of the first cut depends upon the tool used 

 and the skill of the user, similarly for the value of re. If for in- 

 stance re could be made 1/16 instead of 1/8 inch it would reduce 

 the space between the side arms of the herring bone from (> inches 

 to 3! assuming the value for / to be constant. Whether this would 

 be too close for practical work, whether the areas drained by the 

 separate cuts would seriously overlap is not known, on this point 

 experiments are needed, because it is certain that before long a 

 special tool to cut a thin shaving not more than 1/16 inch will be 

 available. 



Then the value of /, the times of reopening, is at present not 

 fixed. Various values ranging from 10 to 25 have been assigned 

 as suitable. Experimental results are here needed, and probably 

 # each estate will eventually have a special value for this quantity. 

 For the moment it can be safely assumed that 15 is not too high 

 a value. 



