REMARKABLE INCREASE OF TEMPERATURE AFTER DARK. 



205 



times of the day are recorded. On the 27th, the day's shade 

 maximum temperature reading had reached 91-8° about 10 a.m., 

 and with the N.N.E. breeze the temperature as usual decreased, 

 till at 7 p.m. the reading in the louvred screen stood at 75°. 

 Shortly after, a thunderstorm, which had been working up from 

 the westward for about half an hour previously, now involved us 

 within its influence, and instead of experiencing the usual 

 expected cooling breeze accompanying such a phenomenon we were 

 prostrated by a blast as from a furnace. In a few minutes the 

 temperature rose to 86°, and at 815 p.m., after the disturbance 

 had passed, my maximum shade thermometer reading stood at 

 955° instead of 91*8°. Thus the hot air of this thunderstorm 

 was three and a half degrees warmer than the air in the screen 

 during the hottest part of the forenoon. 



The phenomenon is the more remarkable when it is remembered 

 that it occurred quite after dark, in fact I was outside taking 

 photographs of the lightning accompanying the disturbance when 

 the first blast struck us. The force of the wind was fresh to 

 strong and came from the W.N.W., that being the point of the 

 compass that the disturbance itself bore down upon us. Bearing 

 in mind these conditions, it will be noted that heat-wave was 

 directly connected with the electric disturbance, and as the 

 phenomenon passed to the eastward, the prevailing northerly 

 breeze re-asserted itself, and the temperature decreased to its usual 

 condition. The total duration of the phenomenon with its 

 abnormal conditions was thirty minutes. 



In the attached table will be seen the shade temperature read- 

 ings at 8 a.m., the dry and wet bulb at 9 a.m., the daily shade 

 maximum readings, and also the maximum reading in the sun's 

 rays : — 



Date. 



November 



Shade Temperature in Louvred Screen. 



Maximum reading 

 in Sun's rays. 



8 a.m. 



9 a.m., Dry. 



9 a.m., Wet. 



9 a.m., Max. 



27 

 28 

 29 



81° 

 84° 

 87° 



83° 

 86°8 



87°4 



69°4 



o 



721 



76°4 



92° 



91 ? 8 



95°5 



159°8 



153° 



150° 



