[9] WORK OF THE STEAMER FISH HAWK. 11 



was the last trip of the season, aud preparations were then made for 

 leaving the station. During the 9th and 10th specimens and other ar- 

 ticles were received on board for transportation to Washington. 



The dredging apparatus worked satisfactorily during the season, and 

 no changes suggested themselves except in the method of registering 

 the Negretti & Zambra deep-sea thermometer. 



The Tanner case, described in my report of last year, is all that can be 

 desired in the depths usually sought by the Fish Hawk; but, in antici- 

 pation of more extended explorations on board the Albatross, we con- 

 sidered it necessary to devise some method of registering in deep water 

 without the necessity of waiting for the descent of a messenger. 



The propeller on the Sigsbee water bottle suggested a simple and re- 

 liable method of reversing at any desired depth and would permit the 

 use of any number of instruments in series. 



I called the attention of Passed Assistant Engineer William L. Bailie 

 to the matter, and he devised the plan shown on Plate II. Fig. 1 shows 

 the instrument clamped to the sounding wire ready for use ; Fig. 2 

 shows a front view of the case, and Fig. 3 a vertical sectional view of 

 the Bailie attachment, which consists of the propeller and slip-hook in- 

 closed in a metal case which screws to the upper end of the Tanner 

 case, the slip-hook having been removed for the purpose. 



To use the thermometer, clamp it to the sounding wire, as shown in 

 Fig. 1, and the action of the propeller will close the hook and retain the 

 wire during the descent. As soon as the ascent is commenced the pro- 

 peller is set in motion, bringing the screw in the upper end of the spin- 

 dle into action, gradually raising the propeller until the small part of 

 the spindle at the lower end (Fig. 3) allows the hook to open, releasing 

 the wire, when the thermometer capsizes and registers the temperature 

 by breaking the column of mercury. 



The drift or distance which the thermometer must move through the 

 water before capsizing is regulated by a set screw, and can be varied at 

 pleasure between the limits of 3 and 10 fathoms. 



Later in the season we received several of the Magnaghi improved 

 frames which, also, depended upon a propeller for reversing. They 

 were not well adapted for use on sounding wire, and were not, therefore, 

 much used. 



The frame above mentioned is the device of Commander Magnaghi, 

 of the Italian Navy. The following description is taken from the adver- 

 tisement of Messrs. Negretti & Zambra. 



NEGRETTI & ZAMBEA'S PATENT IMPROVED-FEAME STANDARD DEEP- 

 SEA THERMOMETER. 



"The apparatus will be best understood, short of inspection, by ref- 

 erence to Plate III (Nos. 1 and 2). A is a metallic frame in which the 

 case B containing the thermometer is pivoted upon an axis, H, but not 



