Meteorological Observations for December 1829, 159 



General Observations. — The first part of this month was dry, and alter- 

 nately mild and frosty : tiie latter part was unprecedentedlycold for Decem- 

 ber, with a prevailing N.E. wind, which brought on a high pressure the 

 last six days. 



The 5th instant was foggj', with the exception of three hours in the af- 

 ternoon, and was the mildest day in the month. The morning of the 15th 

 was also foggy, and the maximum temperature for the twenty-four hours 

 occurred in the night. On the iJOth a sufficient quantity of snow fell to 

 cover Portsdown Hill. It again snowed on the 22nd, and on the 24th and 

 25th nearly three inches in depth fell here, the greater part of which dis- 

 appeared by evaporation, the other part remained on the ground till the 3rd 

 of Januarj', in places shaded from the sun's rays. On the 26th the moats, 

 marshes and ponds in this neighbourhood were firmly frozen, and tiirongecl 

 with skaiters and sliders. Early in the morning of the 28th the thermo- 

 meter receded to 18 degrees, and one that had been exposed on a bed of 

 snow the preceding night, stood at the same time at 14 degrees. A large 

 steel magnet (which had also been exposed to the frost) held in the hand 

 a quarter of a minute, to bring down the metallic float of a thermometer 

 at the time of this low temperature, so benumbed the fingers, as to render 

 the touch insensible for several minutes. On the 29th the maximum tem- 

 perature did not exceed 29 degrees. 



The mean temperature of the external air this month is 12-27 degrees 

 colder than the mean of December 1828 ! it is also ujjwards of six degrees 

 colder than the mean of December for the last fourteen years, and the 

 coldest December by one degree and a quarter we have ever registered. 



The atmospheric and meteoric phaenomena that have come within our 

 observations this month, are, one lunar halo, four meteors, an aurora bo- 

 realis, and five gales of wind, or days on which they have prevailed; namely, 

 four from the North-east, and one from the East. 



KEMARKS. 



London." — December 1. Fine. 2. Cloudy. <?. Foggy morning: cloudy. 

 4 — 6. cloudy. T.Cloudy: slight fog at night. 8— lO.Fine. 11, 12. Cloudy. 

 13. Very fine. 14, 15. Dense fog. About 10 o'clock a.m. on the 14th the 

 fog was so dense that coachmen and others were obliged to lead their 

 horses. On both nights the mails were detained by it, and iiad to be guided 

 by torch-light. 16. Fine. 17. Cloudy. 18. Stormy with snow. 19,20. 

 Clear and cold. 21. Cloudy, with snow in the afternoon to the depth of 

 two inches. 22, 23. Cloudy. 24 — 28. Clear and frosty. 29. Cloudy and 

 cold, with some sleet at night. 30. Cloudy. 31. Clear and frosty. Ice on 

 the ponds upwards of four inches in thickness. 



Penzance. — December I. Fair: rain. 2. Fair: showers. 3. Clear : rain. 

 4, Fair, 5. Fair: misty. 6. Misty. T.Clear. 8. Fair: misty, 9. Rain : 

 fair. 10. Uain: fair. 11. Fair. 1 2. Rain : fair. 13. Misty. 14. Fair: 

 clear. 15. Clear. IG. Clear: shov.ers. 17. Clear: rain. 18. Hail: 

 showers, &c. 19, 20. Clear. 21. Showers. 22. Hail and snow. 23. Clear: 

 fair. 24. Snow. 25, 26, Clear, 27, Fair. 28, 29. Clear. 30, 31. Fair. 



Jioston. — December 1 — 6. Cloudy. 7. Fine. 8 — 10. Cloudy. II. Fine. 

 12. Cloudy: rain a.m. and p.m. 13 — 16. Fine. 17. Foggy. 18. Fine. 

 J 9. Cloudy : snow early a.m. and rain p.m. 20. Cloudy. 21. Fine. 22, 23. 

 Cloudy.' 24. Stormy. 25. Fine: snow showers. 26, 27. Cloudy. 28. 

 Cloudy : snow shosvers. 29 — 3 1 . Cloudy. 



MeUvro- 



