[77] FISHERIES OF THE UNITED STATES. 589 



Steel Wire used in taking serial temperatures. 

 United States Fish Commission. 

 When several thermometers are to be used, attached to the same 

 sounding wire, for taking serial temperatures in the sea, their combined 

 weight is too great to be trusted to the ordinary sounding wire of No. 

 21 gauge, and a heavier wire is employed. For this purpose the United 

 States Fish Commission has made use of No. 18 wire, American gauge, 

 which has a tensile strength in air of about 600 pounds. The Tanner 

 sounding machine exhibited, is furnished with this size of wire. 



Sounding Leads used in connection with steel sounding wire. Actual 



lead for recovery, and photographs. 



United States Coast and Geodetic Survey and United States Fish Com- 

 mission. 



The sounding leads used by the United States Fish Commission in 

 connection with the steel wire, down to depths of 800 fathoms, are of 

 the ordinary commercial pattern for recovery, with a concave lower end 

 to hold the tallow arming for obtaining a sample of the bottom. They 

 weigh from 12 to 20 pounds. The lead attached to the Tanner sound- 

 ing machine exhibited weighs only 10 pounds. The same style of lead 

 is also employed by the United States Coast Survey for similar depths, 

 but it is furnished with the Stellwagen cup (Sigsbee's Plate, No. 7) for 

 obtaining specimens of the bottom. This cup consists of " a wrought 

 iron spindle, sunk for a part of its length into the sounding lead, and 

 with a detachable, conoidal cup screwed to its lower end. Sliding freely 

 on the spindle, between the lead and the cup, is a leather washer, which 

 is raised by the resistance of the water in the descent or by the resist- 

 ance of the soil on striking bottom. On the ascent the washer falls 

 by its own weight, or by the resistance of the water is forced down upon 

 the cup, thus enclosing the specimen. A second washer of lead was 

 generally used above the leather, and sometimes a piece of muslin was 

 gathered and seized around the spiudle above the washers, allowing its 

 folds to drape down around the washers and cup, nearly to the bottom 

 of the latter. This was intended to prevent a current of water between 

 the spindle and the washers, and the tendency to wash out the speci- 

 men." 



The sinkers for detaching, used on board the Blake in connection 

 with sounding rods, are cast-iron shot, with a hole of sufficient size to 

 give a clearance of one-sixteenth of an inch all around the rod, and 

 weighing about GO pounds each (Sigsbee's plate, No. 39). 



Sigsbee- Belknap Sounding Rod. — Consisting of Commander Charles D. 



Sigsbee's detacher in connection with his modification of Capt. G. E. 



Belknap's (U. S. N.) sounding cylinder No. 2. 



Commander diaries D. Sigsbee, United States Navy. 



The subject of sounding rods, with especial reference to this rod, .is 

 discussed in Sigsbee's Deep-Sea Sounding and Dredging, pp. 39-51, the 



