Meteorological Observations. 159 



phur at ordinary temperatures, remove all difficulties in explaining 

 the results obtained with this substance. The vesicles of sulphur 

 absorb the vapour of mercury with great energy, and when sulphur 

 is employed, nothing prevents the mixture of air with the vapours 

 produced. The principal result obtained in this case may therefore 

 be considered the normal result. 



4. By bringing together the fact observed by Faraday, which is 

 otherwise perfectly correct, and the views of Poisson upon the state 

 of the last strata of the terrestrial atmosphere, the limitation of the 

 vapour of mercury has been employed in the highest discussions of 

 general physics, both in treating of the limitation of the atmosphere 

 of the earth and of the divisibility of matter ; questions which, since 

 the time of Wollaston, have been regarded as correlative. The 

 results of my experiments appear to me to prove that it is impossible 

 to refer to the limitation of the vaporization of mercury in specula- 

 tions of this nature. — Comptes Rendus, Nov. 20, 1854, p. 1013. 



METEOROLOGICAL OBSERVATIONS FOR DEC. 1854. 

 Chiswick. — December 1. Clear and fine. 2. Overcast : very large halo round 

 the moon. 3. Cloudy : clear. 4. Clear and fine. 5. Fine : cloudy : clear at 

 night : rain. 6, 7. Fine : cloudy. 8. Densely overcast. 9. Cloudy. 10. Clear 

 and cold. 11. Sharp frost : fine. 12. Very fine. 13. Hazy: overcast: rain. 

 14. Densely clouded. 15. Dusky flying clouds : overcast : rain. 16. Cloudy : 

 fine. 17. Clear : fine : rain. 18. Rain : heavy clouds : clear and cold : rain. 19, 

 Very fine : rain. 20. Stormy and wet. 21. Fine : rain : overcast. 22. Cloudy 

 and boisterous : rain at night. 23. Fine : cloudy : overcast : rain. 24. Fine : rain. 

 25. Densely clouded : rain : clear and fine. 26. Clear and fine. 27. Fine. 28. 

 Clear and frosty : very fine : frosty. 29. Overcast. 30. Cloudy : fine. 31. Over- 

 cast : cloudy : boisterous. 



Mean temperature of the month 39 0- 35 



Mean temperature of Dec. 1853 32 '49 



Mean temperature of Dec. for the last twenty-eight years ... 39 *64 



Average amount of rain in Dec T50 inch. 



Boston. — Dec. 1, 2. Fine. 3. Cloudy : rain p.m. 4. Fine. 5. Cloudy. 6. 

 Fine : rain a.m. and p.m. 7. Fine. 8. Cloudy. 9. Fine : rain and snow p.m. 

 10,11. Fine. 12. Fine : rain p.m. 13. Cloudy. 14. Cloudy: rain a.m. 15. 

 Fine. 16. Fine : rain a.m. 17. Fine. 18. Rain a.m. and snow p.m. 19. Fine: 

 rain p.m. 20. Rain a.m. 21. Cloudy : rain a.m. 22. Cloudy. 23,24. Fine. 

 25. Cloudy : rain p.m. 26. Cloudy. 27. Fine: rain a.m. and p.m. 28. Fine. 

 29—31. Cloudy. 



Sandwich Manse, Orkney. — Dec. 1. Snow-showers a.m. : hail-showers p.m. 

 2. Snow-showers a.m. : cloudy p.m. 3. Rain a.m. : showers p.m. 4. Showers 

 a.m. and p.m. 5. Showers a.m. : cloudy p.m. 6. Showers a.m. and p.m. 7. 

 Cloudy a.m. : sleet-showers p.m. 8. Showers a.m. : sleet-showers p.m. 9. Showers 

 a.m. and p.m. 10. Bright a.m. : snow p.m. 11. Cloudy a.m. : showers p.m. 12. 

 Sleet-showers a.m. : showers p.m. 13. Cloudy a.m. : showers, thunder and light- 

 ning p.m. 14. Slcet-showers a.m. : showers p.m. 15. Sleet-showers a.m. and p.m. 

 16. Hail-showers a.m. : sleet-showers p.m. 17. Sleet-showers a.m. : hail-showers, 

 frost p.m. 18. Hail-showers, frost a.m. and p.m. 19. Cloudy, frost a.m. : rain p.m. 

 20. Sleet-showers a.m. : clear p.m. 21. Drizzle a.m. : showers p.m. 22. Damp 

 a.m. : sleet-sbowers p.m. 23. Hail-showers a.m. : sleet-showers p.m. 24. Showers 

 a.m. : bleet-showers p.m. 25. Showers a.m.: hail-showers p.m. 26. Snow a.m. : 

 hail-showers p.m. 27. Snow a.m. : snow, clear p.m. 28. Snow, cloudy a.m. : 

 rain p.m. 29. Drizzle a.m. and p.m. 30. Sleet-showers a.m. : hail-showers p.m. 

 31. Showers a.m. : rain p.m. 



Mean temperature of Dec. for twenty-seven previous years . 41°*10 



Mean temperature of this month 39 "13 



Mean temperature of Dec. 1853 38 "97 



Average quautity of rain in Dec. for fourteen previous years 395 inches. 



