CONTENTS. 



Page 



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



Millimetre in the Barometer 89 



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



limetre in the Barometer at different Temperatures and Ele- 

 vations ......... 91 



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 ....... 92 



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



to obtain the True Mean Barometical Pressure, Philadelphia 93 

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

 tion to obtain the true Mean Barometrical Pressure, Greenwich 94 

 XXII. For reducing Minutes into Decimals of an Hour ... 95 

 XXIII. Correction for Curvature and Refraction . . . .96 



2. THERMOMETRICAL MEASUREMENT OF HEIGHTS. 



" XXIV. Regnault's Barometric Pressures corresponding to the Tempera- 

 ture of Boiling Water 98 



" XXV. Regnault's Barometric Pressures corresponding to the Tempera- 

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



" XXVI. Regnault's Barometric Pressures corresponding to the Tempera- 

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



3. APPENDIX TO THE HYPSOMETRICAL TABLES. 



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

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



For converting French Toises into different Measures. 



TABLE I. Conversion of French Toises into Metres . . . . 114 



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



III. Conversion of French Toises 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 . 



VI. Conversion of Metres into Paris Feet 



VII. Conversion of Metres into English Feet 



VIII. Conversion of Metres into American Feet . 



IX. Conversion of Metres into Rhine or Prussian Feet 



For converting Paris Feet into different Measures. 

 X. Conversion of Paris Feet into Toises . 

 XI. Conversion of Paris Feet into Metres 

 XII. Conversion of Paris Feet into English Feet 

 XIII. Conversion of Paris Feet into American Feet 



116 

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 120 

 128 

 128 



129 

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 131 

 132 



D 



