Section III, 1919 [123] Trans. R.S.C. 



On the Latent Heats of Vaporization of Methane and Ethane. 



By John Satterly, M.A., D.Sc, F. R.S.C, and John Patterson, 



M.A., F.R.S.C. 



(Read May Meeting, 1919.) 



In connection with the designing of a column for the manufacture 

 of hehum from natural gas by the condensation process it is important 

 to have some idea of the various heat changes involved, and as natural 

 gas is largely methane with sometimes a considerable proportion of 

 ethane, and as these are liquefied in the process it was desirable to 

 know their latent heats of vaporization. 



The column which we used in our factory at Hamilton was a 

 modification of the ordinary Claude oxygen column, and from it we 

 procured, during our experiments on the production of helium in the 

 early part of 1918, large quantities of liquid methane and ethane. 



In order to get quick results we decided on a simple process. 

 An approximate knowledge of the latent heats is good enough for the 

 purpose of design. We understand that the Bureau of Standards at 

 Washington is engaged on an accurate determination which will, how- 

 ever, take some time. 



Two methods were adopted. In each case the liquid was at the 

 boiling point. In the first method an electrically heated wire served 

 to evaporate some of the liquid, in the second a piece of copper was 

 lowered into the liquid. In both cases the evaporated hydrocarbon 

 was collected over water in a graduated jar and the mass estimated 

 from the volume. The heats supplied were estimated from the wat- 

 tage applied in the first case and from the mass and specific heat of 

 the copper in the second case. 



Method I. The figure gives the arrangement of the apparatus. The 

 liquefied hydrocarbon is placed in a thermos bottle, B, provided with a 

 rubber stopper. Through this stopper penetrate two stout copper leads, 

 LL, which are joined at the lower ends by a nichrome spiral, S. The rest 

 of the electrical connections are shown diagrammetrically. A is the 

 ammeter and V the voltmeter. The gases liberated from the hydro- 

 carbons in the bottle pass by way of bent tubes, TT, and a rubber 

 connection and are collected over water in a graduated litre cylinder, 

 G, standing in a dish, D. 



The experiment was first done with liquid oxygen as a test of the 

 method. The oxygen was placed in the bottle. Exposed to the atmos- 



