[el WORTHY-MURRAY] 



BALLOON FABRICS 



Table III 

 Katharometer Results 



45 



Summary 



1. Tests have been carried out on the permeability to hydrogen 

 and to helium of typical samples of fabrics. 



2. With rubbered fabrics the permeability to helium has been 

 found to be less than to hydrogen, the ratio of the helium to hydrogen 

 permeability being (i) 0-66 by Interferometer method, (w) 0-72 by 

 Katharometer method. 



3. With skin-lined fabrics the ratio of helium to hydrogen per- 

 meability was found to be about unity. 



This investigation was carried out at the Admiralty Physical 

 Laboratory under the direction of Professor J. C. McLennan, F.R.S., 

 Scientific Adviser to the British Admiralty. 



South Kensington, 

 14th April, 1919. 



