THE HEAT OF THE SUN. n 



lesser hall. There will be twice as many rows of seats in 

 it, and each row will contain twice as many chairs. 

 Accordingly four times as many people can be accommo- 

 dated in the large hall as in the small one. The buildings 

 being after the same design the number of exit doors will 

 be of course the same in both halls. Each door of the large 

 hall will, in conformity with our supposition, be double as 

 wide and double as high as the corresponding door in the 

 small one. Let us now suppose that both these halls are 

 filled to their utmost capacity, and that in each of them 

 a panic breaks out among the audience from an alarm of 

 fire, or from some similar cause. Would the facilities of 

 escape be equal from the two buildings, and if not, which 

 of them would have the advantage ? Considering that 

 the two buildings have been erected from the same 

 designs, it might at first appear that the facilities for 

 a rapid emptying of the buildings should be equal in 

 both; but this is not the case. No doubt the larger 

 building has double the width of door exit possessed by 

 the small one, but, on the other hand, four times as many 

 people have to push through these doors, and consequently 

 the crowding at the exits of the large room would be 

 double as great as at those of the small one. In a pre- 

 cisely similar way it would appear that if one of the 

 buildings had ten times the linear dimensions of the 

 other, it would have ten times as many rows, and each 

 row would have ten times as many seats, so that the whole 

 audience contained in the large hall would be a hundred- 

 fold that contained in the small one. The width of door 

 exit would, however, be only ten times as great, and 

 consequently the crushing and crowding and the diffi- 



