192 Humboldt on Isothermal Lines, and the [March, 



spring, 57°; summer, 70-8°; autumn, 58°* Mem. Inst. 1812. 

 p. 49. Cotte, mean temperature, 51 - 2°. 



31 Wahlenberg. Flor. Carp. p. 90. Continental elimate. 

 Height of the observatory, 474 feet. 



3S Two years, near Boston, in New England. Transatlantic 

 climate. The thermometer sometimes descends to 0°. 



33 Eleven years (1803 — 1813) of observations made at the 

 observatoiy. A greater number of years will, perhaps, give the 

 mean temperature a little higher. Vaults, 53°. Kirwan finds 

 for Paris, from seven years of observations of unequal value, 

 5L6°; he fixes upon 52-7°. Cotte, from 29 years of observa- 

 tions (Journ. de Phys. 1782, July), 53-2°. Cotte, for 33 years, 

 (1763—1781, Mem. Instit. iv. 266), 52-4°. The extraordinary 

 year of 1816 offers the mean temperature of 48 - 8° ; winter, 37*2° ; 

 spring, 49°; summer, 59*6° ; autumn, 50°: the preceding year, 

 1815, offers a mean temperature of 50*8° ; winter, 37-2° ; spring, 

 52-7°; summer, 62-8°; autumn, 50-8°. Arago. Mean temper- 

 ature of Montmorency, for 33 years, 50*8° ; height, 498 feet. 

 Cotte. Strasburg, lat. 48° 34' ; height, 480 feet ; mean tempera- 

 ture, 49*2°. Herrenschneider. 



54 Dr. Young. Mean temperature varies from 47*8° to 51*4°, 

 (Lectures, ii. 453). Cavendish (Trans. 1788, p. 61), 48-8°, 

 Roebuck, Hunter, and Kirwan, 51-6°. Horsley, 51-8°. Accord- 

 ing to Kirwan, the four seasons in London are, 39 - 6°, 50*9°, 

 64-8°, 52°; at Paris, 36-2°, 51°, 66°, 52-6° ; from which results, 

 London, 51*2°; Paris, 52-4°. Cotte (Journ. de Phys. xxxix. 

 36) thinks London is 51-2°, and Paris, 52-4°. The difference 

 which we observe in cultivated plants depends less upon mean 

 temperature than upon direct light, and the serenity of the atmo- 

 sphere. 



35 Seven years. Cotte. Lisle, 48*4° ; Rouen, 5P4° ; Cam- 

 bray, 52° ; Soissons, 53-4° ; Rethel, 53-2° ; Metz, 53° ; Nancy, 

 52°; Etampes, 51°; L'Aigle, 49-8°; Brest, 54-2°; Mayenne, 

 52°. 



36 Mohr, and Van Swinden. Five years. 



37 Thirteen years. Temperature rather too high ? 



38 Eleven years. Van Swinden. From 1771—1783. Mean 

 temperature, 5l"2°. 



39 Concave transatlantic summit. Seven years of observa- 

 tions give 54-8° ; for the four seasons, 34°, 52°, 75-2°, 56-2°. 

 Rush, 52-6 (Drake's View of Cincin. p. 116). Coxe, 54-2°. 

 M. Legaux finds for 17 years, for Springmill on the Schuylkill, 

 lat. 40° 50' ; mean temperature, 53-4. Springs, near Philadelphia, 

 54-8°. Warden. 



40 Two years only. Retif de la Serve. The thermometer 

 sometimes descends to — 4° in the parallel of Naples ! Springs, 

 54-8°. Ipswich, lat. 42° 38' ; mean temperature, 50°. Williams- 

 burg, in Virginia, 58-1°. Cotte and Kirwan. Transatlantic 

 climates. 



