set output 'sound_air_speed.ps' 
set term postscript color enhanced 'Helvetica,18'  
set style line 1 lt rgb 'red' lw 3  
set style line 2 lt rgb 'green' lw 3  
set style line 3 lt rgb 'blue' lw 3  
set style line 4 lt rgb 'cyan' lw 3  
set style line 5 lt rgb 'violet' lw 3  
set grid 
set key bot right 
set ylabel 'Speed of sound (m/s)'  
set xlabel 'Frequency (Hz)' 
set logscale x 
set title 'Speed of Sound in air, from Evans and Bass (1972)' 
plot [][343.40:343.60] './sound_air.txt' index 0 using 1:($2*304.8)         with points ls 1 ps 3 pt 6 t ''  
set output 
quit 
