314 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



The improved dredgiuj,^ quadraut is a lelinemeut of the iiistrunieut 

 described on page 04, lleport ou the Coustructioii aud Outfit of the 

 U. S. Fish Commission steamer Albatross. In its present form the 

 frame A A consists of two pieces of black walnnt 2 feet in length, half 

 an inch thick, and 2 inches wide, screwed together with brass screws, 

 forming a water-tight joint. One of the pieces has a semicircular exten- 

 sion at its center, which supports the scale C C. 



Fig. 1 represents the (juadrant ready for use. Figs. 2 and 3 show it 

 with the two parts of the frame separated, bringing into view the 

 method of construction. Fig. 4 is an end view at D, and Fig. 5 is a 

 sectional view of rod D and spring E. 



Nomenclature: A A, frame, of black walnut; B, pendulum, of brassj 

 C C, scale, of brass; D, rod, brass, controlling elliptical spring; E, 

 spring catch, of brass. 



The i)eiiduluni, B, 4 inches in length, moves freely on a friction bear- 

 ing, and has on its upper extremity a disk with milled surface. The 

 rod, 1), is attached to and controls an elliptical spring which, when in 

 action, grips the milled surface of the disk on the pendulum aud holds 

 the latter in position while the reading is taken. The spring catch, E, 

 holds the rod, D, in place when it is pressed in for the purpose of dis- 

 tending the elliptical spring to allow free movement of the pendulum. 

 It engages a slot cut in the rod D, for the purpose. The scale, C C, is 

 graduated on each side of the semicircle from a vertical to a horizon- 

 tal position, the latter reaching 90°. The instrument is intended to 

 measure the angle of dredge rope when operating in deep Avater, where 

 a change too small to be noticed by the eye might carry the trawl many 

 fathoms off the bottom. 



To use the quadrant, take it in both hands, press the rod D with the 

 right hand until the spring catch E engages the slot on D; take a 

 favorable position and incline the instrument until its upper edge is in 

 line with the dredge rope, then press spring catch E with the thumb 

 of the right hand, disengaging the rod D, and thus locking the pendu- 

 lum B, when the angle from the vertical can be read on the scale. 



We have now the j)erpendicular (depth) and hypothenuse of a right- 

 angled triangle (amount of dredge rope out and its angle). With these 

 elements enter table 2 in Bowditch and obtain the third element neces- 

 sary to complete the triangle, Avhen it will be seen whether the trawl 

 is on the bottom or not, due allowance having been made for catenary 

 curve of the rope. 



There have been several changes in the personnel during the year. 

 Ensign C. M. Fahs, U. S. Navy, reported for duty Septcunber 5, 1892; 

 Ensign W. B. Fletcher, U. S. Navy, was detached September 14, 1892; 

 Passed Assistant Surgeon T. A. Berryhill, U. S. Navy, reported January 

 5, relieving Passed Assistant Surgeon F. W. F. Wieber, U. S. Navy, who 

 was detached January G, 1893; Lieut. C. G. Calkins, U. S. Navy, was 

 detached January 7, being relieved by Lieut. A. F. Fechteler, U. S. 

 Navy, who re])orted the same day; lOnsign W. G. Miller, U. S. Navy, 

 was detached January 25; Passed Assistant Paymaster J. S. Cari)enter5 



