NEGRETTI AND ZAMBBA, HOLBOKN VIADUCT, E.G., 



FIG. 85. 



FIG. 84. 



95. Wet and Dry Bulb Hygrometer for external Window use, with 

 engraved Opal Glass or Porcelain Scales, mounted on a substantial and 

 Ornamental wood and metal bracket, fitted with a clamping screw for setting 

 the scale at any convenient angle for observation, as fig. 85. 



Price 2 10 and 330 



96. Portable Wet and Dry Bulb Hygrometer, (fig. 86.) A most 

 compact and convenient form of Hygrometer, invented by Negretti and Zambra, 

 as a companion instrument to their Small Patent Maximum and Minimum 

 .Registering Thermometers and Pocket Aneroid Barometer (figs. 26 and 61), 

 pages 26 and 51. The Hygrometer, with stand and water cistern, is fitted 

 into a neat Pocket case. Price . . . .220 



Larger Standard size . 2 10 



