92 INCUBATING OVENS AND THERMO-REGULATORS. 
maintain a small flame which must not be sufficient by itself to keep 
up the desired temperature in the water bath. 
Altmann has recently (1891) described a thermo-regulator which 
is made by Miincke, of Berlin, and which is shown in Fig. 65. This 
is said to act with great precision. It is a modification of Reichert’s 
b 
Fic. 65. Fie. 66, 
regulator. Its mode of action will be readily understood by a refe- 
rence to the figure. 
A thermo-regulator which gives very accurate results, which are 
not influencel by differences in pressure, is that invented by the 
ce 
Whe 
- 
Fic. 67. 
writer over thirty years ago. The regulating thermometer may 
contain mercury only, or air and mercury, as shown in the thermo- 
regulator for gas (Fig. 59). In the simplest form a large bulb con- 
taining mercury is used, and a platinum wire is hermetically sealed 
in the glass so as to have contact with the mercury (Fig. 66, q). 
