74 
POPULAE SCIENCE EEVIEW. 
dredging of coral is that used by those who carry on the fish- 
ing on the coast of Algiers. This consists of a frame composed 
of two beams of timber about six feet in length arranged cross- 
wise_, and having a heavy weight attached below the point of 
intersection ; to the extremities of the beams are attached nets 
of a coarse material and about a yard in depths and finally, the 
whole machine is fastened by a ring at its centre to a powerful 
rope, the other end of which is connected to the capstan of a 
boat. By pulling this apparatus over that portion of the sea-bed 
in which the coral exists, the branches are smashed off from 
their rocky attachments, and becoming entangled in the net- 
work are afterwards brought to the surface and removed. The 
Spaniards use a kind of instrument called a gratte, whose 
principle is somewhat similar, but in which iron projections 
are employed, and a machine of like kind though slightly 
modified is the salabre, which is now seldom employed. Indeed 
it is considered by those competent to judge in such matters, 
that the employment of engines composed of iron is highly 
detrimental to the coral, inasmuch as it destroys even those 
parts which it does not remove. The scapliandre is simply a 
kind of clothing similar to that used by ordinary divers, and 
from the head-piece of which tubes proceed to allow of the 
entrance of pure air and exit of the respired gases, the former 
being blown in by an apparatus contained in the boats. 
According to M. Lacaze-Duthiers, this appliance cannot be 
employed with advantage, as, besides the constant danger 
attending its use, the weight and pressure are too great, and 
the surface of the sea-bottom too rugged to admit of its being 
used profitably or conveniently. A species of diving-bell has 
also been tried, but for the reasons above stated it is even 
more objectionable than the scapliandre. 
The fishing on the Algerian shores is very extensive, and 
employs ovor two hundred boats, ranging in burden from 
sixteen to four or five tons. The value of the coral annually 
collected by them has been variously estimated. Thus we 
find that according to the statistics of the compilers of the 
Catalogue of the Exhibition of 1862, the value of the coral 
fished annually should amount to 4,448,000 francs ; for there 
were 204 boats engaged in the fishery in 1860, and according 
to the London statistics the average per boat would be about 
23,000 francs. This estimate, however, M. Lacaze-Duthiers 
shows to be far beyond the mark. In the year to which we have 
referred the weight of coral taken amounted to 29,888 kilo- 
grammes, and the value of this, according to calculation, was 
1,448,950 francs, or about £60,372 of our money. It appears to 
be the opinion of all those conversant with the character of the 
fishery, that it is, at present, owing to the ineflBcient protection 
