REMAEKS ON DK. PEARSON'S REVIEW. 129 



position could not be found during a certain November, they 

 had therefore been silted over. Enormously larger areas than 

 that occupied by these tanks have repeatedly been missed. 

 Exceedingly skilful navigation combined with a large percentage 

 of luck is required in order to locate an area eight yards square 

 situated ten miles out at sea. The obvious explanation is that 

 the tanks were missed, and there is not the slightest proof 

 or probability that the tanks were actually silted over. 



The acceptance of this evidence by Dr. Pearson is curiously 

 at variance with the critical attitude adopted by him in the 

 rest of his Paper. During the six successive November in- 

 spections which I attended, these tanks were found on every 

 occasion except one. In the latter case the weather was so 

 bad that inspection work was impossible, and consequently 

 the search for the tanks could not be carried out thoroughly. 

 The time occupied in locating these tanks has varied in my 

 experience from three hours to two weeks. But when located 

 they were never found to be covered with sand, even though 

 the maximum silting effects of the south-west monsoon would 

 then be apparent. The comiter-effects of the north-east 

 monsoon referred to by Captain Legge could at that time of 

 the year have produced no change, as that monsoon had 

 hardly commenced. 



We stated in our report that large " pot-holes " occur on 

 certain parts of the pearl banks. If sand drifts about, why 

 are these pot-holes never filled up ? We never assumed that 

 the danger to oysters, caused by a bottom current, lies merety 

 in the fact that oysters will be swept away. The danger of 

 driftmg sand was very fully recognized ; but any movement 

 of the bottom water which would produce silting sufficient to 

 cover and destroy a bed of oysters, say a half-mile square, 

 must be very great, and our experience showed conclusively 

 that during the period of our observations no such silting has 

 taken place. Our results were entirely negative, and we could 

 have wished them otherwise, for then the solution of certain 

 obscure problems would have been ob\aous enough. 



Drift Bottle Experiment. 

 Dr. Pearson has, unfortunately, failed to understand the 

 results we obtained, and consequently his remarks on this 

 S 6(5)13 



