45, COENHILL, E.G., AND 122, KEGENT STKEET, W., LONDON. 165 



The scale on the right hand is an ascending one, and on the left descending, 

 as will be seen in our engraving (fig. 336). The thermometer is set for observation 

 by drawing the indices down to the surface of the mercury by a small magnet, which 

 attracts the steel through the glass, so that it is easily moved up or down. They 

 should be drawn nearly to the top of the tubes when it is desired to remove the 

 instrument, which should be carefully carried in the vertical position ; for should 

 it be inverted, or laid flat, it may become put out of order. For transmission by 

 ordinary conveyances, it requires that attention be given to keep it vertical. Six's 

 Registering Thermometers should be always hung strictly in the shade. 



These Thermometers, when carefully made and adjusted to a standard 

 thermometer, are recommended as very convenient for ordinary purposes, where 

 strict scientific accuracy is not required. 



FIG. 333. 



FIG. 331. 



FIG. 335. 



FIG. 336. 



326 Six's Registering Thermometer, 8-inch Boxwood Scale, E s ach d 



plain tube .... 



327 Ditto ditto, enamelled tube . ! ! 



328 Ditto ditto, with bevelled edges . 



329 Ditto with 8-inch Zinc or Boxwood scale, in 



Japanned Metal case . 



330 Ditto ditto, 10-inch .'.!". 



331 Ditto ditto, 12-inch, Porcelain Scale (fig. 331) 



332 Six's Registering Thermometers, with Opal Glass 



scales, in japanned Metal cases (figs. 331 and 336) 



12s. 6d., 21s. 1 



Copper cases, 3s. extra. 



Each. 

 s. d. 



076 

 086 

 10 6 



10 



15 



1 1 



10 22 



