TABLES 



COMPARING THE QUANTITIES OF RAIN-WATER. 



The three kinds of measures which are most in use for noting the quantities of 

 rain and melted snow, are the Centimetres and Millimetres m France, the Paris or 

 French inches and lines in Germany, and the English inches and decimals in Eng- 

 land, America, and also in Russia, the Russian foot being the same as the English 

 foot. The following tables will facilitate the comparison of these various measures 

 with each other. 



A glance at the tables will show that the first column on the left contains the 

 numbers to be converted, and the heads of the following columns the fractions of 

 these numbers, or units, each of which is one tenth of those in the first column. 

 Shorter tables, at the bottom, give, when necessary, the value of proportional parts 

 still smaller than those found in the larger tables. 



Example. 



Let 13 Centimetres be converted into French inches and lines. 



Take, in Table IL, the line beginning with 10 Centimetres in the first column, fol- 

 low that line as far as the column headed 3 Centimetres, and there will be found the 

 number of 4 inches 9.63 lines, which is the corresponding value in French inches of 

 10 -\- 3, or 13 Centimetres. 



If the number is followed by a fraction, as for instance, 13.5 Centimetres, or 135 

 Millimetres, we find, — 



French Inches. Lines. 



In the larger table 13 Centimetres = 4 .9,63 



In the smaller table at the bottom 5 Millimetres = .2,216 



Or 13.5 Centimetres = 4.11,846 



When the measures which are to be compared are both subdivided into decimal 

 parts, the equivalents of the numbers greater than 9.9 may be found by moving the 

 decimal point. 



Example. 



Let 346.7 Centimetres be converted imo English inches. 

 In Table I., in the column headed 4, on the fourth line, 



we find 3.4 Centimetres = 1.3386 English inches. 



Moving the decimal point by two places we have 



340 Centimetres = 133.86 English inches. 

 Then, in the column headed 7, on the 



line beginning with 6, we find 6.7 Centimetres = 2.64 



Making together 346.7 Centimetres = 136.50 English inches. 



B 161 



