and Consolidation of the Dunes of Gascony. 437 
generally not higher than that of the wattled fence ; they have 
also been found better, and it is recommended that they be used 
in preference. 
The " gourbet {^Calamagrostis arcnaria'), Syn : Ammophila 
arenaria, which is ordered to be mixed with the broom and 
with the pines in places most liable to be invaded, is a hardy 
plant, and does not suffer from the proximity of the sea ; and it 
has, besides, a special quality valuable for the purpose in view, 
which is, that in proportion as the sand accumulates round 
its stem it continues to grow without injury, while almost all 
other plants are killed when the sand is raised above the crowns 
of their roots. The gourbet has been known to continue to grow 
vigorously after it had been covered slowly with more than 8 feet 
of sand since it was sown. The stem of the plant buried in the 
sand was nearly 10 feet from the end of its root. 
The gourbet is, as we have said, a very hardy plant ; and as it 
grows at all seasons, and is not affected by either heat or cold, 
there is no doubt that it would suit the climate of Beirut. 
The sea-pine which grows on the dunes of Gascony is a 
s])ecies which succeeds marvellously in the climate of the south- 
west of France ; and besides the timber, it gives a considerable 
produce in resin, so that it has naturally been chosen in a climate 
which suits it so well ; but it has not succeeded except in a 
temperate climate, and does not do well either in great heat or 
cold. I am strongly of opinion that it would not be grown easily 
at Beiriit ; but other species might be found there, more suited 
to the climate, which might be substituted with advantage for the 
sea-pine. The residents in that country are more competent than 
I can be to know which would be the most suitable species. The 
process of sowing and fixing the drifting sands would in other 
respects remain the same, whatever be the species of pine made 
use of. 
The dunes which have been sown in the departments of the 
Garonne and of the Landes are, I believe, the highest on the sea- 
coast. Their mean height is from 160 to 230 feet. There are 
some in the middle of the chain which attain the height of 
260 and 300 feet. 
The total surface of the dunes in the two departments is over 
200,000 acres. 
The work of fixing these dunes, begun by Bremontier, was 
continued by the engineers who succeeded him, according to his 
system, and was completed in 1862 over the 200,000 acres. 
The system invented by Bremontier is shown in the annexed 
Specification. It has always been applied with the same success. 
I have often seen, during the progress of the work, the most 
violent storms, producing the greatest destruction in the dunes 
