Introduction. 7 



TABLE 4. Millimeters to be subtracted from barometer (brass-scale) 

 readings to reduce them to C. 



The correction necessary to be applied to readings obtained from 

 a barometer having a brass scale, in order to change them to a tem- 

 perature of C., is given to 0.01 millimeter mercury for temperatures 

 ranging from 11.0 to 36.0 C. and for barometric pressures from 740 

 to 780 millimeters. The table is used in connection with calcula- 

 tions of reduction of gases to 760 millimeters, where a brass-scale 

 barometer has been used. The top argument is pressure every 10 mil- 

 limeters. The side argument is temperature every 0.5 C. It is from 

 Landolt-Bornstein Physikalisch-chemische Tabellen, 1905, page 35. 



TABLE 5. Logarithms of p/760 for barometric pressures between 700.0 

 and 780.9 millimeters. 



This table is calculated by subtracting the logarithm of 760 from 

 the logarithm of the barometric pressure corrected to 0C. It is 

 used in computing the reduction of gas volumes to a pressure of 760 

 millimeters, where p equals the observed pressure corrected to C., 

 by means of table 4. 



TABLE 6. Logarithms of t n/vnv? j f or temperatures between 11.0 



1+U. 



and 36.09 C. 



The table is calculated by computing the cologarithms for values 

 of 1+0.00367 1, where t equals the temperature in degrees centigrade. 

 It is used in calculating the reduction of gas volumes to C. from 

 observed temperature t. The top argument is from 0.00 to 0.09 C. 

 The side argument is in tenths of a degree centigrade. 



TABLE 7. Logarithms for the reduction of saturated volumes to 

 C. dry and 760 millimeters pressure. I ^ Q oo367~t X 7607 



t = temperature, p = barometric pressure corrected to 0C., 

 and e = pressure of aqueous vapor at t. 



This table is calculated by subtracting the pressure of aqueous 

 vapor (e) at t as found in table 3, page 30, from the barometer reading 

 p corrected to C. for scale correction. The logarithm of p/760 is 

 then found in table 5, page 32, and added to the logarithm of 

 1 /I +0.00367 t as found in table 6, page 34. The table is useful for the 

 calculation of reduction of gas volumes to and 760 millimeters 

 where the volumes are measured under conditions of atmospheric 

 pressure, known temperature, and saturated with aqueous vapor 

 such as expired air collected in a spirometer or passed through a 

 wet-gas meter. The top argument gives the barometric pressure in 

 millimeters. The side argument gives the temperature t to 0.1 C. 



