Ivi INTRODUCTION. 



Table 84. Density of air at different temperatures Centigrade. 

 This gives values and logarithms of the expression 



^ 0.00129305 



^t, 760 = 



I + 0.00367/ 



for values of / extending from — 34° C. to 69° C. The tabular values are 

 given to five significant figures. 



Density of air at different humidities and pressures — Metric measures. 



Table 85. Term for humidity: values ^ 0.378 <?. 



1-^7 r ^^ b — o.^l^e 



Table 86. Values of —— = ^ 



760 760 



Table 85 gives values of 0.378^;' to hundredths of a millimetre for dew- 

 points extending by intervals of 1° from —30° C. to 50° C. The values of 

 Broch's vapor pressures (<?) corresponding to these de^v-points are given in a 

 second column to hundredths of a millimetre. The table is thus conveniently 

 used when either the vapor pressure or the dew-point is known. 



Table 86 gives values and logarithms of -— - = ^ — for values of 



760 760 



h extending from 300 to 800 mm. The barometric pressure b is the barom- 

 eter reading corrected for temperature and 0.378 <? is the term for humidity 

 obtained from Table 85. The logarithms are given to five significant figures 

 and the corresponding numbers to four decimal places. 



Table 87. Conversion of avoirdupois pouyids and ounces into kilogrammes. 



The latest comparisons made by the International Bureau of Weights 

 and Measures between the Imperial standard pound and the "kilogramme 

 proto-type " result in the relation : 



I pound avoirdupois = 453.592 427 7 grammes. 



This value has been adopted by the United States Bureau of Weights 

 and Measures and is here used. 



For the conversion of pounds, Table 87 gives the argument for 

 every tenth of a pound up to 9.9, and the tabular conversion values to 

 ten-thousandths of a kilogramme. 



For the conversion of ounces, the argument is given for every tenth of 

 an ounce up to 15.9, and the tabular values to ten-thousandths of a kilo- 

 gramme. 



Table 88, Conversion of kilogrammes i7ito avoirdupois poiinds and ounces. 

 From the above relation between the pound and the kilogramme, 



I kilogramme = 2.204622 avoirdupois pounds. 

 = 35.274 avoirdupois ounces. 



