CONTENTS. 



Table XVIII. Height, in Metres, of a Column of Air corresponding to a 

 Millimetre in the Barometer ...... 



" XIX. Height, in Metres, of a Column of Air corresponding to a Mil- 



limetre in the Barometer at different Temperatures and Ele- 

 vations ......... 



" XIX'. Height, in English Feet, of a Column of Air, corresponding to 



a Tenth of an Inch in the Barometer, at different Tempera- 

 tures and Elevations ....... 



" XX. Correction to be applied to the Means of the Flours of Observation 



to obtain the True Mean Barometical Pressure, Philadelphia 



" XXI. Correction to be applied to the Means of the Hours of Observa- 



tion to obtain the true Mean Barometrical Pressure, Greenwich 



" XXII. For reducing Minutes into Decimals of an Hour . 



" XXIII. Correction for Curvature and Refraction ..... 



Page 



89 

 91 



92 



93 



94 

 95 

 96 



2. Thekmometrical Measurement of Heights. 



XXIV. 



XXV. 



XXVI. 



Regnault's Barometric Pressures corresponding to the Tempera- 

 ture of Boiling Water ....... 98 



Regnault's Barometric Pressures corresponding to the Tempera- 

 ture of Boiling Water, revised by Moritz, in Metrical Measures 102 



Regnault's Barometric Pressures corresponding to the Tempera- 

 ture of Boiling Water, revised by Moritz, in English Measures 104 



3. ArPENDix TO THE FIypsometrical Tables. 

 Comparison of the Measures of Length most generally used for indicating AUiludes. 

 On the Various Standards of Measure, and their Relations .... 109 



For com:eriing French Toifes into (lijjcrcnt Measures. 



Table I. Conversion of French Toiscs into Metres . . . . 114 



" II. Conversion of French Toises into Paris Feet . . . .114 



" III. Conversion of French Toiscs into English Feet . . . 115 



" IV. Conversion of French Toises into American Feet . . .115 



For converting Metres into different Measures. 



" V. Conversion of Metres into Toises . . . . . . 116 



" VI. Conversion of Metres into Paris Feet .... 117 



VII. Conversion of Metres into English Feet .... 120 



" VIII. Conversion of Metres into American Feet ..... 128 



" IX. Conversion of Metres into Rhine or Prussian Feet . . . 128 



For converting Paris Feet into different Measures. 



" X. Conversion of Paris Feet into Toises ...... 129 



" XI. Conversion of Paris Feet into Metres . . . . IHO 



" XII. Conversion of Paris Feet into English Feet . . . .101 



" XIII. Conversion of Paris Feet into American Feet . . . 132 



D 4 



