502 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [12] 
pass through and to admit heat and light, all of which are necessary for 
the development of the eggs. 
In case it should be impossible to construct any of the apparatus de- 
scribed above, and to carry on the incubating process in water-courses, 
one may, in pure run- . 
ning water which 
leaves no sediment, 
employ boxes like the 
one shown in Fig. 13, 
or the boxes of Messrs. 
Genin and: Rem y. 7 
These last-mentioned ——= 
boxes are used at 
Scharnhouse. In order 
to avoid the dangers 
threatening the spawn from the oxidation of the tin, Professor Rueff 
has had them made of zine, and supplied them with floats. Vessels 
of glazed terra cotta are also employed, which have all the advantages 
= of the Rueff boxes, and are less ex- 
pensive (Fig. 14). Some piscicultur- 
ists prefer, in spite of the disadvant- 
ages mentioned above, flat wicker 
baskets, with or without floats (Figs. 
15 and 16), according to the habits 
=. of the fish whose eggs are to be incu- 
= bated. 
== Coste * has also constructed an in- 
= Se raat, cubating-box which will remedy all 
the defects of the other boxes. This box (Fig. 17), which is an improve- 
ment on the Jacobi box, measures about 1 meter and one-half meter 
breadth and depth. Its sides and bottom are of solid wood. Its top is 
formed of a lid in two parts, 
in the center of which there 
is a grating of metal wire; 
and each end is closed by a 
door, whose opening is larger 
than that of the lids, and is 
also supplied with a grating. 
Both doors and lds move on 4 
hinges, open outward, and are ® 
closed simply by means of two 
small bolts fastened with Fie. 15. 
strings, and, for greater safety’s sake, supplied with padlocks. There 
are no subdivisions in the inside of this box, but there are running along 
the sides small ledges to support the frames. These frames are of wood 
Fig. 13. 
*CosTE: Comptes-Rendus, p. 55 et seq. 
