358 



Scientific Proceedings, Royal Dublin Society. 



last by 64 ! This extraordinary concourse of fortunate circum- 

 stances makes it possible to base on these numbers the following 

 exceedingly simple tables for the conversion of imperial and me- 

 trical measures into one another. 



Measures of Length. 



yard 

 foot 

 inch 

 ^ inch 



= 914*4 mm. 

 = 304-8 „ 

 = 25-4 „ 

 = 127 „ 



metre = 39*37 inches. 



lb. 

 i lb. 

 i lb. 

 2 oz. 



oz. 



Weights. 

 = 453*6 grammes. 

 = 226*8 

 = 113*4 

 = 56*7 „ 

 = 28*35 



grain = *0648 „ 

 gramme = 15*4321 grains. 



Correction, 1 in cases 

 which require the last 

 degree of refinement. 



Subtract 9 from 

 every million. 



Add 11 to every 

 million. 



Subtract 16 from 

 every million. 



( Add 16 to every 

 f million. 



Liquid Measure. 



gallon 

 \ gallon 

 quart 

 pint 



h P int 

 naggin 



i naggin 



fluid oz. 



= 4544 



- 2272 

 = 1136 

 = 568 

 = 284 

 = 142 

 = 71 

 = 28*4 2 



cc. 



Subtract 1 from 

 every 10,000. 3 



/ 



1 All the corrections are subtractive when British is being converted into metric 

 measure, and are, consequently, additive when converting metric into British. 



2 This is the correction to make the result accord with the weight of a cubic inch of 

 distilled water, weighed in air against brass weights, at the temperature of 62° F., and 

 barometer pressure of 30 inches, as determined by the Eoyal Commission appointed in 

 1816. To make the result conform to the more recent determination, the correction 

 to be subtracted is six parts in every 10,000. Neither correction is beyond the limits 

 of uncertainty in the determinations. 



3 The number of cubic centimetres in a British fluid oz. exceeds the number of 

 grammes in an oz. weight, because of the expansion of water between the temperature 

 of its greatest condensation and 62° F. 



