326 
BULLETIN OF ’ THE UNITED STATES FISH COMMISSION. 
bulb, wliicli, grasping the wire, held the thermometer in a vertical position during its 
deseeut and, when ready to haul up, the latch was disengaged by the impact of a 
metallic messenger sent down on the wire, and the thermometer promptly capsized by 
the preponderance of weight, the shot having been blocked in the free end of the case. 
The next improvement, introduced a few days later, was simply a brass tube, 
seven-eighths inch in diameter, in which the thermometer was placed and held in 
position by rubber rings. The bulb end was secured to the sounding line by a lan- 
yard and the other end carried a pair of slip hooks, which, encircling the line, insured 
a vertical position, bulb down, during its descent. It was reversed by impact of a 
messenger, as before, and, having no buoyancy, it retained its i>osition, bulb up, even if 
the reeling in was interrupted or the vessel was laboring in a seaway. Tlie messenger 
was of brass, cylindrical in form, with rounded ends, and weighed from 3 to 4 ounces. 
This device became known as the Tanner case and i)roved efficient in the mod- 
erate depths sought by the Fish Hatch, but, in anticipation of more extended explora- 
tions on board the Albatross, then under construction, I considered it necessary to 
devise some method of registering in deep water without the loss of time incident to 
the descent of a messenger. The propeller of the Sigsbee water bottle suggested a 
simple and reliable method of reversing at any desired depth and permitting the use 
of any number of instruments in series. 
The attention of Passed Assistant Engineer William L. Baillie, IT. S. N., being 
called to the matter, he devised the propeller attachment which screwed to the upper 
end of the Tanner case, the slip hooks being removed for the piu'pose. The action 
of the j)ropeller is practically the same as in the Magnaghi frame, received later in 
the same year. The device became known as the Baillie-Tauner case. It operated 
perfectly, so far as the promjit and unfailing overturning of the thermometer was 
concerned, but the weight, bulk, and general form of the free end was such that it 
subjected the delicate instrument to undue jarring on the way up, frequently shaking 
the mercury down from the bulb or catch reservoir into the tube and vitiating the 
observation. It was used in common with the Magnaghi frame, each having its 
merits, but both were lacking in some essential qualities and were superseded late in 
the season of 1883 by the device described below. 
THE TANNER IMPROVED THERMOMETER CASE AND SIGSBEE CLAMP, USED 
WITH THE NEGRETTI & ZAMBRA DEEP-SEA THERMOMETER. 
Fig. 1, plate xxi, shows the apparatus complete, and flg. 2 a vertical sectional 
elevation of the metal case containing the thermometer. The frame is of brass, cast 
in one piece, as light as is consistent with the required strength. 
The case/’ is a brass tube of commercial pattern, 1 inch in diameter. It has a 
I)ieceof metal soldered in its lower end to support the spiral spring h, and pivots to the 
frame at^’. The cap i is screwed upon the upper end of the case, and is pierced with a 
central hole for the recej)tion of the spindle o, carrying the propeller n, which is 
secured to it by a through drift pin. The upper part of the spindle has a screw thread, 
which works in a thread in the head of the frame. Its lower part has a plain surface, 
witli rounded end, and revolves freely in its bearing and in the hole in the caj) i. The 
set screw p regulates the distance the thermometer must be drawn up through the 
water before it is overturned and the temperature registered. The range is from 3 to 
25 fathoms. The clamp q is the Sigsbee clamp used by him on water bottles and the 
IVIiller-Casella deep sea thermometer. It is of i)hosphor bronze and performs its work 
admirably either on the stray line or sounding wire. When clamping to the latter. 
