66 
through the interior. I visited St. Pierre near the west 
side and then Boyardville on the north, and was much 
struck by the admirable way in which by this system of 
artificial irrigation great tracts of what would otherwise 
probably be waste swampy land are made good use of. 
Some of such claires, canals and salt pans are shown in 
Pl. III, fig. 3. I found the canal at Boyardville on July 7th 
to be 70°F. with a specific gravity of 1023; while on the 
same day at 11 a.m. and in the open sea, half way between 
the islands of Oléron and Ré, the temperature was 72°F. 
and the specific gravity 1:025. On that same day the 
temperature of the sea at Port Erin in the Isle of Man 
was 60° F'., at 10 a.m.,and the following day at 3 p.m. 
it was 68°F'., the highest temperature we have registered 
in the open sea at Port Erin this summer—the shore 
pools often become considerably warmer, e.g., 76°F. 
La RocHELLE. 
The shores in the neighbourhood of Rochelle are in 
part limestone, in some places very much broken up so as 
to be merely masses of separate stones, and in part a fine 
mud. On the rocks and stones are many small “natural” 
oysters which are collected by the people at low tide. 
Those I tasted were of poor quality and saltish in flavour. 
I found the temperature of the sea near Rochelle to be 
82°F ., the highest temperature I met with except on the 
pares at Arcachon. In the fish market at Rochelle I saw 
very small iminature soles and plaice exposed for sale in 
quantities ; also mussels which were small, from 1} to 13 
inches in length, but very good; and also cuttlefishes and 
various kinds of crabs. 
I had intended going next to the Island of Re, but 
heard at Rochelle that it would scarcely be worth while, 
so I decided to visit the mussel bouchots in the Bay of 
Aiguillon. 
