34 



DISCOVERY REPORTS 



Six out of these twelve sub-samples give a range of variation from this mean of 

 from — 26 to 1- 1 per cent. 



Nine out of these twelve sub-samples give a range of variation from this mean of 

 from — 32 to + 26 per cent. 



The twelve sub-samples give a range of variation from this mean of from — 37 to 

 + 45 per cent. 



The sub-sampling of the St. 41 D sample gave somewhat similar results: 

 Sub-samples 1/40 of whole sample 1280 640 640 



1/60 



giving a mean of 826. 



Six out of these twelve sub-samples give a range of variation from this mean of 

 from — 19 to + 21 per cent. 



Nine out of these twelve sub-samples give a range of variation from this mean of 

 from — 23 to + 26 per cent. 



The twelve sub-samples give a range of variation from this mean of from — 37 to 

 + 55 per cent. 



All these sub-samplings were carried out by the author who made the N 70 V 

 analyses, and in addition he carried out a series of sub-samplings of a sample contain- 

 ing a known number of organisms. This sample included 1000 medium Calanoids, 

 and was sub-sampled thirty-eight times by eight different methods. The numbers 

 estimated as being in the sample are as follows, according to the sub-samples taken : 



50 per cent of the sub-samples show a range of variation from the actual number in 

 the sample of from — 20 to 4- 20 per cent. 



75 per cent of the sub-samples show a range of variation from the actual number in 

 the sample of from — 28 to + 26 per cent. 



90 per cent of the sub-samples show a range of variation from the actual number in 

 the sample of from — 44 to + 45 per cent. 



100 per cent of the sub-samples show a range of variation from the actual number in 

 the sample of from — 75 to + 65 per cent. 



