METEOROLOGICAL INSTRUMENTS. 



the tube should be first shaken by 

 gently tapping the front of tin* 

 frame with the back part of the 

 fingers, from three to five times. 



Plain Barometer. (Fig. 604.) 

 Barometers are mounted in a 

 variety of styles ; the figure re- 

 presents one in a neat polished 

 mahogany frame, having a ther- 

 mometer on one side of the scale, 

 and a screw at the bottom of the 

 reservoir or cistern of the barome- 

 ter for the purpose of forcing the 

 mercury up, which, filling every 

 part of the tube, renders the in- 

 strument portable, and may be 

 carried in a horizontal or other 

 position in transportation. 



Price, $10.00. 



Barometer with Glass Door. 

 (Fig. 605.) This has a neat frame 

 of mahogany or rosewood, with 

 round or square top, and having a 

 small door with glass in front of 

 the scale, with thermometer and 

 portable screw, as described in the 

 preceding figure. 



Price, $11.00. 



" with vernier subdividing 



the graduations to 100 



of an inch, $12.00. 



