398 Meteorological Observations for Sepiemher 1829. 



in the N.E. quarter from 9 hours 48 minutes till 10 hours p.m. It exhi- 

 bited a bright, but ahnost colourless arc of a great circle; and when in the 

 densest part of the nimlins it reflected a bow above, about the same parallel 

 distance as the exterior is seen from the interior solar rainbow. This phse- 

 nomenon very rarely happens, and it is the first time that we have observed 

 an exterior lunar iris, which from the age of the moon, only 9j days, was 

 naturally faint by reflection. The apparent width of the interior iris at its 

 brightest appearance was two degrees, and its diameter on the horizon 

 72 degrees, which corresponded nearly with the measurement of a solar 

 rainbow between 6 and 7 o'clock the preceding morning. 



In the afternoon and evening of the 14th, heavy haii-Ehowers fell here, 

 accompanied with ligiitning and thunder. A large lunar halo in the even- 

 iu<' of the 15th, and solar halos in the mornings of the 16th and 17th, were 

 succeeded by heavy rain and strong gales. 



The last five or six nights the hoar frost was prevalent, and thick in the 

 "rass fields early in the mornings. This is certainly an early beginning of 

 wintery weather. 



The mean temperature of the external air this month is remarkably low, 

 beinsj four degrees under the mean of Se])tember for the last fourteen years, 

 and four-fiftiis of a degree under the coldest September during that period. 

 The temperature of spring water arrived at its maximum for the year on 

 the 7th. 



The atmospheric and meteoric phaenomena that have come within our 

 observations this month, are, one lunar and five solar halos, three meteors, 

 four rainbows, and one double lunar iris, lightning on four days, and thun- 

 der on two; and ten gales of wind, or days on which they have prevailed ; 

 namely, one from the North-east, two from the South-east, one from the 

 South, five from the South-west, and one from the West. 



KEMARKS. 



Lonr/o?!.— September 1,2. Cloudy. S,4.Veryfine. 5. Cloudy. 6.Fine, 

 with slight showers. 7. Fine : rain at night. 8. Fine morning : heavy rain 

 in the afternoon. 9. Very fine : i-ain at night. 10. Wet morning: stormy, 

 with showers: strong gale at night. 1 l.Fine morning: stormy and wet, with 

 stron" "ale at night. 12. Cloudy: with some thunder and rain at 3 p.m. 

 13. Fine moruini' : cloudy. 14. Fine. 15. Fine morning: cloudy, with 

 he:ivy thunder-storm at 4 p.m. and much rain. 16. Wet morning: stormy. 

 17. Cloudy: heavy rain at night. 18. Foggy, with slight showers. 19. Wet 

 morning : fine. 20. Fine : rain at nigiit. 21 — 25. Very fine, with slight fugs 

 in the morning, and at night. 26. Very fine : drizzly at night. 27. Drizzly : 

 cloudy. 28. Fine morning : cloudy. 29, 30. Foggy in the mornings : very 



fine. 



Penzance. — September 1 — 4. Fair. 5. Fair : showers. 6.Fair. 7. Clear: 

 showers. 8. Showers, hail, and rain. 9. Fair. 10. Rain. 1 l.Fair: rain. 

 1 2. Fair : showers. 13. Rain. 14. Fair. 15. Fair: rain. 16. Rain. 17. Fair: 

 rain. 18. Rain. 19. Fair. 20. Clear: rain. 21. Clear. 22.Fair. 23. Rain 

 ;it ni"ht. 24. Clear. 25. Fair. 26. Rain. 27.Fair: showers. 28. Showers. 



29. Clear : showers. 30. Clear. 



Z^osto;;.— September 1. Cloudy. 2 — 4. Fine. .<;, 6. Cloudy, 7. Fine: 

 rain at nioht. 8. Rain. 9. Fine. 10. Rain. 11. Cloudy: rain early a.m. 

 and P.M. 12. Fine. 13. Fine : rain at night. 14. Cloudy : rain p.m. 15. Fine. 

 16. Cloudy. 17. Fine : rain early A.M. 18. Cloudy. 19. Rain. 20. Fine. 

 21. Fine: rain early a.m. 22 — 24. Rain. 25. Fine. 2C. Cloudy. 27. Rain : 

 bcauiifid rainbow quarter past six a.m. 28. Fine. 29. Fine: rain p.m. 



30. Fine. 



Mdcoro - 



