Report of the commissioner for 1878 : part VI.

  • United States Fish Commission.
Date:
1880
Catalogue details

Licence: Public Domain Mark

Credit: Report of the commissioner for 1878 : part VI. Source: Wellcome Collection.

    1139/1174 (page 959)
    choose common wire-clotli, 12 wires to the inch or finer. The article sold at all the hardware shops for window screens is very suitable; being already painted thoroughly it requires but a single coat of asphaltum varnish to fit it for use. All iron wire must be protected from rust by painting or varnishing in a most thorough manner. The commonly used material for this purpose is asphaltum varnish. The so-called paraffine varnish, a coal-tar product, is much inferior. It is very uneven in quality, but generally dries very slowly and has a penetrating and disagreeable odor. It is best to have the wire-cloth cut of the proper size, rolled perfectly flat, and then varnished with two or three coats on the edges that are to lie against the wooden frame. The rest of the varnishing can be done after the wire is attached to the frames. Two good coats, very carefully laid on, is the least that will answer for iron not previously painted, and three coats are much td be preferred. For nailing to the frames use tinned tacks. • There is, after all, a good deal of trouble in securing a thorough spreading and adhesion of the varnish, and it is much to be hoped that some better material will soon be discovered. I have tried iron wire, tinned after cutting up, and for a single season it has worked well; but I fear the tin will not be permanent enough. Brass wire, nickel-plated, is admirable but expensive,—costing about 60 or 70 cents per square foot. For the present, therefore, iron wire is recommended. There should always be a surplus of trays, so that if any of those in use are found to rust badly they can be exchanged for newly varnished ones. 9.—ARRANGING THE TRAYS FOR WORK. The trays must not be placed on the bottom of the trough, but on a support raised a little distance above the bottom. As it is very desirable to have the trough as free as possible from obstructions, it is best*to pro- vide a temporary support for the trays, like that shown in Figure 8. Take a long, narrow strip of wood a quarter of an inch thick and drive Fig. 8. through it, at proper distances, nails one inch long. Set the points of the nails a quarter of an inch into the floor of the trough and the top of the strip will then be three-quarters of an inch above the floor. On two of these sup- ports, placed at a distance of a quarter or half inch from the sides and run- ning the whole length of the trough, rest the hatching-trays. Supports touching the sides of the trough will not answer, because they form, with