ON COMMON NOTIONS OF PROBABILITY. 11Q 



fatal, would present at least 20,000 chances. Before an 

 individual is born, it is, say 2 0,000 to 1 against his dying 

 at a given age of a given malady ; and yet, even with 

 such imperfect observations as exist at present, it begins 

 to be seen that uniformity is the law of large masses 

 compared with each other. I will illustrate this by 

 some cases. Few things appear more varied than the 

 distribution of maladies, that of criminal acts, and that 

 of the sex of children in different families. I have 

 taken purposely a case of evil, physical and moral, and 

 one which is neither. The experience of any one 

 individual might lead him to say that it is no uncommon 

 thing for three or four times as many persons to die of 

 consumption in one period of five years as in the 

 previous period ; but the experience of one large city 

 will show that such is not the case. The bills of mor- 

 tality in London showed the following results; the 

 upper line denoting the last year of the five in question, 

 and the lower line the average number in every thousand 

 deaths which were caused by consumption, or what was 

 called such.* 



1732 3737 1742 1747 1752 1757 

 135 163 165 180 ]87 197. 



Here is nothing like enormous fluctuation. The 

 gradual increase of the number shows an increasing 

 tendency to the complaints then described under the 

 head consumption, but cannot be called fluctuation, being 

 itself regular. 



The number of murders committed in the whole 

 extent of any one country might be supposed liable to 

 very large yearly fluctuation, and still more the compara- 

 tive numbers committed with different classes of weapons. 

 A few years ago, extreme derision would have followed 

 the assertion that the sword and pistol would be felo- 



* The known loose manner in which these Tables were put together 

 does not affect the argument, further than to favour its conclusion. The 

 chances of error in the description increase the probability of fluctuation 

 in the results. 



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