182 OYSTBE CULTIVATION AT FALMOITTH. 



observation during the next two days. On the morning of the 

 third day the crab was dead ; but the mollusk was there 

 unharmed and healthy. 



Before the March winds began to blow, those tiles on which 

 young oysters were detected were removed to Bar Pool which 

 had already been prepared for their reception. This pool, which 

 is about an acre in extent, was used, many years ago, to store sea- 

 water in ; this water being utilized, when the tide was out, to 

 work a very picturesque corn-mill, of which the rapidly decaying 

 remains still form one of the attractions of Falmouth. In those 

 days the greater part of the wheat consumed in Falmouth was 

 ground in this mill ; but now, owing to the present rapid means 

 of transit both by sea and land, flour comes from far off regions ; 

 and almost fifty years have passed since the mill was in working 

 order. To put this pool into a serviceable condition, some fifteen 

 hundred tons of mud had to be removed ; and an even layer of 

 fine gravel, about four inches in depth, was spread over the 

 bottom. In addition to this, the old sluice-gates were replaced 

 and the stone wall which forms the western boundary of the pool 

 was repaired up to a certain height ; so that one is now able always 

 to keep a uniform depth of water in the pool of about one metre. 

 This water is changed twice every day by the tide. The average 

 temperature of the water in the pool is high, the rising tide 

 having to pass up a narrow channel which is sheltered from the 

 winds, but exposed to the sun's rays. Hence the average 

 temperature is about four degrees higher than that of the water in 

 the inner harbour. As a natural consequence, diatoms, which 

 form about ninety per cent, of the food of the oyster, abound here, 

 and during neap tides, when the tide is only sufficiently high to 

 just change the water in the pool, a uniform yellowish film of 

 almost pure diatoms can be observed resting on the thin layer of 

 mud in certain places. This feature is stiU more noticeable if the 

 sun has been shining uninterruptedly for some hours previously. 



TJha latissima flourishes, and during the past summer the 

 screens which guard the entrances to both sluices have been 

 almost forced in, on more than one occasion, by the quantities of 

 weed carried up on the flowing tide. Indeed no inconsiderable 

 amount of the annual grant has been spent in removing this 



