NEGRETTI AND ZAMBRA'S 



DESCRIPTIVE CATALOGUE. 



STANDARD 

 METEOROLOGICAL INSTRUMENTS. 



THE practical usefulness of Meteorological Instruments as weather indicators, 

 and their increasing employment for Scientific and Sanitary investigation, 

 render a knowledge of their construction and principles desirable to all. 

 Impressed with the idea that we shall be supplying a want, in giving simple 

 descriptions of those now in use, we have endeavoured to condense such 

 information regarding the instruments used in Meteorology in the present 

 section of our Catalogue. 



Every Meteorological Instrument of any practical value being described, 

 with plain instructions for using them, purchasers will be enabled to select 

 such as seem to them most suited to their requirements. 



For convenience of reference and comparison we arrange and describe the 

 different instruments used for Meteorological observation under the following 

 headings, viz. : Instruments to show, 1st, the pressure of the atmosphere; 2nd, 

 the temperature of the air ; 3rd, the absorption and radiation of the sun's heat 

 by the earth's surface ; 4th, the humidity of the air ; 5th, the amount and 

 duration of rainfall ; 6th, the direction, the horizontal pressure, and the velocity 

 of winds ; 7th, the electric condition of the atmosphere, the prevalence and 

 activity of ozone, magnetic, and tidal phenomena, &c., &c. 



B 



