96 



PHYSIOGRAPHY. 



[chap. 



the upper part of the scale of the barometer, ranging from 

 29 inches to 3o|- inches. The height of the mercury is 

 seen at a glance by the thick black lines, and we thus not 

 only learn what it was in London at i a.m.- on the morning 

 of issue, but can compare this with the readings for the 

 same hour on the three preceding days. Thus it is seen that 

 on the 31st, the barometer stood at about 30-05 inches; on 

 the 30th, it was 29-86; on the 29th, 29'8i; and, on the 

 28th, it stood at 29-58 inches. It is evident, therefore, from 



CorrectecL to seorlevel, ocnoL reduced/ to 32?Ji 



Fig. 23. — Daily News barometer chart. 



this report that the mercury has been steadily rising. Such 

 comparative readings are of great value, inasmuch as the 

 character of the weather is dependent, not so much on the 

 absolute height of the barometer, as on whether the mercury 

 IS rising or falling, and whether moving slowly or rapidly. 

 It should be added that the recent barometer charts of the 

 Daily News indicate the extreme variations of the instru- 

 ment by means of dotted lines. 



The barometer chart published by the Daily Telegraph 



