100 REPORT OF COMMISSIONER OF FISH AND FISHERIES [98] 



Plate LTIT shows the apparatus properly adjusted on the steel- 

 wire dredge rope ready for use. The cylinder A is suspended to the 

 friction clamp by the tumbler P, and confined to the dredge rope by 

 means of the fairleaders I I. The friction buffer is clamped to the rope 

 beneath the cylinder, and the messenger is shown above the apparatus 

 in the act of descending. 



Plate LIV shows a detailed plan of the cylinder as follows: Fig. 1, 

 a vertical sectional elevation; Fig. 2, a side view; Fig. 3, a top view; 

 and Fig. 4, a bottom view. The copper cylinder A is secured to the 

 wrought-iron frame B by brass screws, and at the bottom of the frame 

 there is a flap or clapper valve 0, which is pivoted at E and opened 

 inwards. It is actuated by the levers D D. The wire sieve F is damped 

 to the top of the cylinder A ; the sieve G is inside of the cylinder A, 

 and is supported on the top of the frame or trap H ; the latter being- 

 supported on a brass ring secured to the inner surface of the cylinder 

 A, and is held in place by brass clamps. Both the sieve G and the 

 trap H are readily removed. 



The steel-wire dredge rope on which the cylinder travels is seen in the 

 fairleaders I I, where it is held in place by the rollers J J. 



Fig. 1 of Plate LY is a side view of the friction buffer; Fig. 2 is a 

 sectional elevation; Fig. 3 is a top view; and Fig. 4 is also a top view 

 with the steel face-plate removed. 



The frame A of the bufferismadeof brass ; the sliding chocks E and S, 

 adjusting screw T, compression spring U, and regulating screw V are of 

 steel. The sliding chocks work in the apertures in the frame as shown 

 in Figs. 2, 3, and 4. Their bearing surfaces are corrugated and their in- 

 ward movement is limited by studs which are part of the frame and fit 

 loosely within a slot in the chocks. 



* " In clamping the buffer to the rope the chock E is always screwed 

 in until stopped by its stud ; the steel rope is therefore always pressed 

 between the two chocks by the elastic force of the spring, which may be 

 regulated as desired. To regulate the buffer for any definite frictional 

 resistance, clamp it to the rope, and move the regulating screw V well 

 inward ; then suspend from the buffer a weight equal to the resistance- 

 decided upon. Move the regulating screw outwards until the buffer 

 slides down the rope under the influence of the suspended weight. 



" Since the chock E is always screwed down in clamping the rope, the 

 buffer remains regulated for prolonged use with the same resistance ; 

 and if the latter proves satisfactory it is probable that the regulating 

 screw need not be touched again for a whole cruise, if the buffer is 

 rinsed in lye- water each time after use." 



Fig. 5 is a top view of the friction clamp, and Fig. 6 a side view. The 

 frame K is of brass; the sliding chocks L and M, adjusting screw N, 

 and eccentric tumbler P are made of steel. 



Fig. 7 is a side view of the messenger X, Fig. 8 a sectional elevation, 



* Sigsbee. 



