45, COENHILL, E.G., AND 122, REGENT STREET, W., LONDON. 



171 



FIG. 398. 



FIG. 399. 



FIG. 400*. 



FIG. 400. FIG. 402. 



NEGRETTI AND ZAMBRA'S 

 PATENT SELF-REGISTERING MAXIMUM THERMOMETER 



For ascertaining Underground Temperature, the Temperature of Mines, Thermal 

 or Boiling Springs, Air Shafts, Atmospheric Temperature, &c., &c. 



397 The above engravings represent various forms of Negretti and Zambia's 

 Patent Self-Registering Thermometers, each adapted to a special purpose ; these 

 can be made available in many other ways not here specified. The principle on 

 which these instruments is constructed, and the ^manner of using them, are fully 

 set forth on pages 42 and 43. 



Particular instructions are supplied with each Thermometer. 

 Fig. 398 represents a Brewer's or Drying Room Self-Registering Thermometer, 

 by which accurate temperatures may be ascertained in positions inconvenient 

 of access, or where Steam, Heat, or Darkness render the true readings of an 

 ordinary Brewer's Thermometer almost impossible to be obtained. 



Price in Stout Copper Case, 110 



Fig. 399 shows another form of the Thermometer divided on its stem, 

 arranged in a Glass Sheath mounted on a Mahogany Board or Metal Plate, 

 for ascertaining temperatures in Hot Air or Drying Chambers, Baths, 

 Ovens, &c., &c., serving as a check on temperatures during absence ; or, as 

 described pages.43 and 46, as a Marine Atmospheric Maximum Thermometer. 



Price, 110 



398 



399 



