[6'3] U. S. FISH COMMISSION STEAMER ALBATROSS. C5 



A longitudinal sectional elevation of Sigsbee's detacher and his modi- 

 fication of Captain Belknap's sounding cylinder No. 2 is shown in Fig. 

 1 ; a side view is seen in Fig. 2, with the sinker hung. Fig. 3 shows a 

 plau view of the cylinder and a longitudinal sectional elevation of the 

 detacher. Fig. 4 shows, a back view of the detacher. The perforated 

 plate j and cylindrical ring d are shown in Fig. 5, and an enlarged view 

 of the hollow cone i, cylindrical ring d, apertures p for the escape of 

 water, and the upper end of the cylinder a are shown in Fig. 6. 



The cylinder a (Fig. 1) is attached rigidly to the guide stem c, the 

 poppet valve/ is on its seat at ee, and the hollow valve stem encircles 

 the guide stem c, and is held in place by the spiral valve spring //,. The 

 hollow cone i moves freely on the upper guide stem; dd is a cylindrical 

 ring forming the base of the cone i, and, when raised during the descent 

 of the sinker, as in Fig. 1, it permits the water to flow freely from the 

 cylinder through the apertures pp into the cone at dd and out at pp; 

 but during the ascent it rests on the top of the cylinder a, closiug the 

 apertures (Fig. 6) against all outward pressure. 



To take a sounding and bring up a specimen of the bottom, bend the 

 stray line to the swivel lc. slip the sinker on and hook the bail r on the 

 tumbler m ; lock the pawl and tumbler and suspend the weight of sinker 

 and sounding rod from Jc, where it will remain until the weight is relieved 

 by the sinker striking the bottom. The pawl will then assume a hori- 

 zontal position from its own weight (Fig. 3); the tumbler will be thrown 

 out of action by the spring n, assisted by its excess of weight at the 

 point of contact with the bail r, thus releasing the sinker. 



When the cylinder strikes the bottom, the valve/ will be forced up, 

 and more or less of the interior space of the cylinder will be filled with 

 a specimen of the bottom soil. As soon as the ascent begins the valve 

 /reseats itself, and, the apertures at the top being closed, the specimen 

 is hermetically sealed. On reaching the surface it is removed by un- 

 screwing the cylinder at b. 



This apparatus has performed its work perfectly; in fact it has never 

 failed to detach the sinker and bring up a specimen when the bottom 

 was reached. They were furnished by D. Ballauf, Washington, D. 0., 

 at $15 each. 



SINKERS. 



All soundings exceeding the capacity of an ordinary hand lead-line 

 axe made with wire; in depths of over 2,000 fathoms a 60-pound de- 

 tachable sinker is used; between 1,000 and 2,000, a 35-pound sinker, 

 also detachable; and from 500 to 1,000 fathoms, an ordinary 35-ponnd 

 ship's lead is used and reeled back. In depths less than 500 fathoms 

 lighter leads, from 18 to 25 pounds weight, are used and reeled back, 

 the bottom specimen being brought up by the arming. 



The detachable sinkers are made of cast iron and are furnished by 

 the ordnance department, navy yard, Washington, D. 0., fitted and 

 bailed ready for use. 

 H. Mis. 67 5 



