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Kansas Academy of Science. 



and, therefore, whether that difference when increased by its 

 proper multiplier is to be added or subtracted. The formula 

 does not specify this. It must be understood that every term 

 is a minuend from which the preceding term is to be sub- 

 tracted. When the preceding term is the greater, then the 

 difference becomes a minus quantity and is to be subtracted in 

 the general addition instead of added. When no term precedes, 

 as in the case of the first term, then is to be subtracted and 

 the term itself becomes a difference. 



