Stoney — On the Determination of Gaseous Volumes, etc. 391 



Both of these corrections are additive, for more zinc is required 

 to produce 7 litres of gas at 15° than at 21°, and again more to 

 produce 7 litres of gas under a barometric pressure of 31" than 

 under 30", the standard pressure. 



Hence our former result has to be increased by 5-J- per Vq 



cent., which brings it up to 20*01 grammes for the weight iq 



of zinc that will evolve 7 litres of gas at 15° under a 19 



barometric pressure of 31". 19 



This is very nearly identical with the result that would 19 



be furnished by the usual much more complicated for- 

 mute. — 



SCIEN. PROC. R.D.S. — VOL. VI., PART VIII, 2 H 



