ABBREVIATIONS AND NOTATION 
Amort. = Amortization. 
Ann. = Annual. 
Beg. = Beginning. 
Eq. = Equal. 
Payt. = Payment. 
A = the annual replacement requirement for each dollar of capital invested 
annually in a growing plant. 
Am = the accrued amortization in m years when the annual amortization in- 
stallment is @ and the interest rate is 7. 
A’ = the amount of $1.00 at compound interest at the end of the nth year 
at the interest rate 7. 
A” = the amount of an annuity of $1.00 paid at the end of each year at com- 
pound interest at the interest rate i. 
an = the amortization installment which must be invested annually, in 
order to amount at compound interest to $100 in n years. 
a,’ = the annual installment which at compound interest at the rate 7 will 
amount to $1.00 in 7 years. 
an!’ = same as an’ when annuity is applied at the beginning instead of at end 
of year. 
an'"’ = the annuity receivable at the end of each year which $1.00 will buy 
for n years. 
am = the current amortization in the mth year, i.e., the amortization incre- 
ment a plus interest on the amortization fund already accumulated. 
It is the amortization installment which in the remaining years of 
life will retire the remaining capital. 
C = cost of replacing a group of articles. 
¢ = the annual renewal requirement for a group of articles whose cost of 
replacement is C. 
e = expectation, that is the probable remaining years of usefulness of any 
article whose probable life new was » years. 
¢ = relative expectancy of an article whose probable life new is 10 years 
when compared with an article m years old whose probable life new 
is n years. 
g = the average annual investment in additions to a plant. 
i = the rate of interest per year expressed fractionally — thus for 6 per 
cent; 7 = 0.00. 
m = a number of years. 
m’ = relative age of an article whose probable life new is 10 years, when 
compared with an article m years old, whose probable life new is #n 
years. 
Note: Other symbols are explained in the notes which precede the several tables. 
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