OYSTER AND MUSSEL REPORT. 103 



they place their " collectors " in position. They consider 

 that it is of great importance that the collectors should 

 not be put in the water unnecessarily soon as the tiles are 

 liable to become coated with other things, slime and sedi- 

 ment, which will prevent the oyster spat ("naissain," as 

 they call it) from adhering. 



The collectors are crates (called " gabarets " or "ruches ") 

 of earthenware tiles coated with a lime cement (PL I, fig. 

 2). The tiles are like ordinary roofing tiles. They are 

 about 14 inches in length 6 inches in breadth at one end 

 and 5 at the other, and ^ an inch in thickness The clay 

 they are made of is coarse and of a reddish colour. Later 

 on I saw the tiles being made further up the coast, north of 

 the Gironde, whence they are shipped in coasting vessels. 



The tiles are prepared for use as collectors by being 

 coated with a layer of limy cement which gives them a 

 whitewashed appearance. The cement is made of lime 

 mixed with sea-water and a certain amount of sand so as 

 to form a creamy paste. Different proprietors use slightly 

 different proportions of lime and sand, and in some places 

 hydraulic cement is also used. This process of coating, 

 known as " chaulage," adds about from T x g to | inch in 

 thickness to each side of the tile. It has to be done with 

 some care so that the limy layer may be of the right nature, 

 sufficiently strong and adhesive and yet readily detachable 

 when the right time comes, so that the young oysters may 

 be removed from the tiles without injury and without the 

 necessity of breaking dp the tiles as used to be the case. 

 By the present method the oysters and cement can be 

 scaled off and the tiles preserved for use again the follow- 

 ing year. A dozen or more millions of these tiles are 

 probably employed each year at Arcachon. 



The prepared tiles are arranged in rows inside cases 

 ("ruches") made of sparwork or strips of wood so that the 



