ALTMAXN'S THERMO-REGULATOR 25 



the ether vaporises and causes the mercury to rise, so as 

 more and more to close the obliquely-cut tube until only 

 the lateral hole remains open, and the discharge of gas is 

 reduced to the minimum amount. If the temperature falls, 

 the mixture of alcohol and ether again contracts, the mer- 

 cury sinks, the supply of gas increases, and the temperature 

 of the water rises once more. 



Gartner's thermo-regulator. Gartner has constructed a 

 thermo-regulator which, instead of a safety-aperture, pos- 



Aperture of exit 



Aperture of entrance 



Regulating screw- 



Mercury vessel 



Flo. 13. ALTM ANN'S THXBMO-BBQCLATOft. 



sesses a by-road for the gas, consisting 'of a rubber gas- 

 tube, compressible by means of a screw, to prevent the 

 minimum flame, which must still burn even when the 

 regulator proper has completely shut off the gas-supply, 

 from proving too large if the pressure of gas increases. 



Altmann's thermo-regulator, The thermo-regulator of 

 Altmann is constructed on Giirtner's principle, being pro- 

 vided with a horizontal tube which can be closed by a tap. 



