. Discovery reports. Discovery (Ship); Scientific expeditions. 196 DISCOVERY REPORTS proved unsatisfactory. It frequently slipped and it is almost certain that a simpler pattern, with two screws at most, would prove more efficient. If a large net is lowered rapidly there is a tendency for both net and closing mechanism to slide up the warp, and if this happens the lines by which the messengers for the lower net are attached will break: it is also very likely that when the apparatus slides back to the stop the momentum consequent upon the impact will be sufficient to effect release. This possib
. Discovery reports. Discovery (Ship); Scientific expeditions. 196 DISCOVERY REPORTS proved unsatisfactory. It frequently slipped and it is almost certain that a simpler pattern, with two screws at most, would prove more efficient. If a large net is lowered rapidly there is a tendency for both net and closing mechanism to slide up the warp, and if this happens the lines by which the messengers for the lower net are attached will break: it is also very likely that when the apparatus slides back to the stop the momentum consequent upon the impact will be sufficient to effect release. This possibility was foreseen when the apparatus was designed, and room is made for the insertion of a small stop / at the upper end to prevent any movement in an upward direction. The primary messenger is shown at m and the secondary. Fig. 20. Opening and closing mechanism for large horizontal nets, shown in use. at n: the former is $\ lb. in weight and stream-lined in form, the latter is 22 lb. in weight and apart from the conical extension piece is similar in shape. The smaller messenger travels at a rate of 3^-47 min. and the larger at about 4-5 min. per 1000 m., the speed depending largely on the angle of the warp. The entire apparatus is made of phosphor bronze except for certain pins, at points where exceptional strength is required, which are of steel. Apart from the defects shown in the stop this apparatus proved all that could be desired, but as is explained further on, the results obtained with these large horizontal nets were not always satisfactory. Depth Gauges. To determine with any accuracy the depth at which mid-water nets are being towed is a matter of some difficulty. In most deep-water investigations the data on this point appear to be based mainly on guess-work, and in a recent expedition all attempts to determine the level are abandoned, and the only information given regarding. Please note that these images are extracted from scanned page images that may have been d
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