512 Mr. J. Glaislier's Remarks on the Weather 



From the circumstance of the increasing temperature during 

 the continuance of the halo, both evaporation and the ascend- 

 ing current of air were increasing, and they would be at about 

 their maxima at about 3'^ p.m. From the numbers in the 5th 

 column, it seems the temperature of the dew-point was be- 

 coming less as the temperature was increasing, so that the 

 ascending current not only carried with it all the water then 

 evaporating, but also some of that which had evaporated pre- 

 viously. It seems, therefore, highly probable, that at the time 

 of the appearance of the halo the largest quantity of water 

 was mixed with the air in its locality, and also, as at this place 

 the temperature of the air during the day was without change, 

 and probably below the freezing-point of water, that the de- 

 gree of humidity was at the time at a maximum value. 



As this halo is one of the best ever observed, and it seems 

 to have been dependent upon the humid state of the air, it is 

 very desirable that observations of the dry and wet bulb ther- 

 mometers taken at about the time, should be collected toge- 

 ther from different places, and I should be glad if such were 

 forwarded to me. 



The reading of the barometer during the months of Fe- 

 bruary and March have been remarkable for large fluctuations. 

 Although I have detailed them in the Registrar-General's 

 weekly reports for these months, it is desirable to mention them 

 here also. On February 1, at 6^ a.m., the reading was 29"505 

 inches; this increased to 30*274 inches by February 3, at 9^ a.m. 

 The reading decreased day by day till the 10th, at midnight, 

 when it was 28"598 inches; it then turned to increase, which, 

 during the 1 1th, amounted to one inch nearly; and at noon, on 

 the 13th, the reading was 29'944- inches, when it turned to 

 decrease. On the 15th, at S'^ p.m., it was 29*373 inches. On 

 the 18th, at 9'' a.m., it was 30*333 inches, being the highest 

 during the month. On the 20tli, at noon, it was 29'288 

 inches, which increased to 29*618 inches at midnight, and 

 continued to increase slowly afterwards till the 21st at 9^' a.m., 

 when the reading was 29'684' inches, after which it decreased. 

 On the 23rd, at 6^ a.m., it was 28*888 inches; at midnight it 

 was 29*229 inches; shortly after this it decreased, and con- 

 tinued to decrease till the 26th at 9^ 4-5™ a.3I., when the re- 

 markably low reading of 28*299 inches took place, a reading 

 lower than that of the 18th by 2*034' inches; it then turned 

 to increase, but did not pass the point 29 inches till midnight 

 on the 27th, and reached only to 29*343 inches on the 29th 

 at 9"^ a.m., when it again began to decrease, and by 6^ p.m. 

 again decreased below 29 inches. On March 1st, at 9'* a.m., 

 the reading was 28*530 inches ; it then turned to increase, 

 which during the 2nd amounted to half an inch nearly. On 



