Meteorological Observations. 79 



It had periods of greater and less brightness, but for the most part 

 was steady, something Uke a sunbeam among the clouds, and never 

 had any approach to the rapid motion of the aurora. 



Its colour was pale or whitish in its upper portion, or when it ap- 

 peared contrasted with the dark sky ; but in passing through the red, 

 copper, or orange-coloured sky that prevailed lower down, it partook 

 of its shade, and tinged the thin strata of cloud that lay across it with 

 a brighter hue of their own colour. Fifty-five minutes was the longest 

 period that it was visible any evening. I am told that it also appeared 

 very bright some mornings before sunrise. 



If the phsenomenon was uncommon, so was the state of the atmo- 

 sphere when it occurred. The drought was unprecedented ; only 

 about J^th of an inch of rain falling in April, which is about yoth of 

 the average quantity in that month in previous years. The atmo- 

 spheric pressure was great, the mercury never being lower than 30*07, 

 nor higher than 30*32. The temperature was also high for the 

 month, being 47°" 64, or more than 4° above the average for April. 



The atmosphere was very calm, and the sky near the horizon of 

 that red or copper colour which generally indicates dry and warm 

 weather, so that at last we could anticipate its appearance. I do not 

 presume to explain the mode of its production, but these circumstances 

 may assist others in so doing. 



METEOROLOGICAL OBSERVATIONS FOR MAY 1852. 



Chiswick. — May 1. Overcast: cloudy: clear. 2. Cloudy and cold: frosty at 

 night. 3. White clouds : fine : clear and frosty. 4. Dusky clouds : clear and 

 frosty. 5. Densely clouded : clear and frosty at night, 6. Cloudy : clear. 7. 

 Overcast: very fine. 8. Cloudy: fine. 9. Fine. 10. Fine: rain at night. 11. 

 Boisterous, with heavy shovk^er, partly hail. 12. Heavy rain : thunder. 13. Cloudy : 

 overcast : boisterous at night. 14. Showery and boisterous : clear. 15, 16. Very 

 fine. 17. Slight drizzle : overcast : thunder, lightning and rain at night. 18. Very 

 fine: rain at night. 19. Very fine. 20. Hazy: fine: showers. 21. Overcast. 

 22. Cloudy : clear. 23. Cloudy. 24, 25. Overcast : fine. 26. Rain. 27. Over- 

 cast. 28. Densely clouded. 29. Rain. 30. Fine: cloudy. 31. Fine: cloudy: 

 clear and cold. 



Mean temperature of the month 51°'45 



Mean temperature of May 1851 51 "16 



Mean temperature of May for the last twenty-six years ... 54 "07 

 Average amount of rain in May l'74inch. 



Boston. — May 1. Cloudy. 2. Cloudy : rain a.m. 3, 4. Cloudy. 5. Cloudy : 

 rain a.m. 6. Cloudy. 7. Fine. 8. Cloudy. 9, 10. Fine. 11. Cloudy. 12— 

 14. Cloudy : rain a.m. 15, 16. Fine. 17. Cloudy. 18. Cloudy : rain a.m. and p.m. 

 19. Cloudy : rain a.m. 20. Fine. 21. Cloudy : rain a.m. and p.m. 22 — 25. Cloudy. 

 26. Cloudy : rain p.m. 27—29. Cloudy. 30. Fine. 31. Cloudy. 



Sandwick Manse, Orkney. — May 1. Cloudy: fine. 2. Clear: fine. 3. Cloudy : 

 fine: clear: fine. 4. Cloudy: fine. 5. Drops: fine: cloudy: fine. 6. Clear: 

 fine : cloudy : fine. 7. Drops : rain : clear. 8. Drops : showers. 9. Rain : clear. 

 10. Drops: clear: aurora. 11. Cloudy: showers. 12. Bright: clear. 13. Rain: 

 clear : fine. 14. Bright : showers. 15. Clear: cloudy. 16. Clear. 17. Clear: 

 fine. 18, 19. Clear : fine : aurora. 20—23. Clear : fine. 24. Bright : fine : clear : 

 fine. 25. Clear: fine. 26. Cloudy. 27. Cloudy: fine. 28. Bright: cloudy: 

 showers. 29. Bright : showers : cloudy : hail-showers. 30. Sleet-showers. 31. 

 Sleet-showers : showers. — This month lias been fine, warm and dry. 



Mean temperature of May for twenty-five years previous ... 47°*88 



Mean temperature of this month 50 '49 



Average quantity of rain in May for six years 172 inch. 



