588 Wisconsin Academy of Sciences , Arts , and Letters. 
A CASE FOR REVERSING THERMOMETERS. 
The case used for the reversing thermometers belongs to 
the Tanner 1 type, with modifications which adapt it better 
to the work in hand. The main part of it consists of a brass 
tube 2.5 cm. (1 in.) in diameter and 30 cm. (12 in.) long. 
(Fig. 8 and Plate XXXVIII, fig. 1.) Elongated openings are 
cut in two sides of this tube so that the scale of the thermometer 
may be seen, and the lower end possesses several small holes 
which afford free entrance of the water to the chamber in 
which the bulb of the thermometer lies. The lower end of 
this tube bears a ring outside for the attachment of the line 
and a flat ring on which the lower coil-spring supporting the 
thermometer rests, is soldered inside the tube at this end. 
The upper end of this tube bears threads so that it can be 
screwed onto the top piece of the case. The latter is 2.8 cm. 
in diameter and 5.5 cm. long. On one side of the top is a 
triangular opening through which project the jaws that clasp 
the line and hold the thermometer in an upright position. 
These jaws are mounted on a pin and they are held into the 
upper, narrow portion of the opening by a spring, in which 
position they are closed. The inner ends of these jaws are 
bevelled on their proximal sides so that they open readily 
when the messenger forces them down into the wider por¬ 
tion of the triangular opening, and releases the line. The 
spring which supports the jaws is coiled around the pin 
which supports them, and a second pin a little lower down 
holds the loose ends of this spring. Below this second spring 
is a diaphragm, against which rests the coil-spring at the 
upper end of the thermometer. This diaphragm and the 
screw cap at the top of the case have fairly large openings in 
the center in order to let the water drain out of the case 
quickly. When it is desirable to use more than one ther¬ 
mometer on a line, a small curved arm (Fig. 8, B) is attached 
near the upper end of the long tube. When the thermom¬ 
eters are lowered, a messenger is hung onto this arm by means 
of a line so that when the upper thermometer overturns, the 
messenger for the second is released. In this way several 
thermometers may be used at the same time. 
1 Report of Com. of Fish & Fisheries for 1881, Pt. IX, 1884, p. 25 and 
pis. XIII, XIV, and XVI. 
