6 THE DIFFUSION OF GASES. 



fied in the next chapter in connection with newer values for N and a more 

 trustworthy value of the diffusion coefficient k than can be obtained through- 

 out the vicissitudes of a long time interval of eleven years and a form of 

 diver such as is here used. 



9. Conclusion. — The above data are subject to the different hypotheses 

 stated ; but it has been shown that the results may be obtained by the method 

 described free from ulterior suggestion. It seems to me that detailed inves- 

 tigations of the above kind carried on with reference to both the chemical 

 and the physical properties of the liquid, i. e., with different liquids and 

 different gases at different temperatures and pressures, can not but lead to 

 results of importance bearing on the molecular physics involved. Hence 

 experiments of this kind were begun in this laboratory and such as have 

 matured are reported in the following chapters. 



Obviously in a doubly closed water manometer (U-tube), the unequal 

 heads of the two columns of liquid must in a way similar to the above vanish 

 in the lapse of time. This method seems particularly well adapted to 

 obviate convection, and has also been adopted, though it requires long 

 time intervals. Finally, hydrogen actually shows a measurable amount of 

 molecular transpiration in the daily march of results obtained; but their 

 extremely complicated character was not foreseen at the outset. They are 

 not, therefore, available for discussion until they have been thoroughly 

 analyzed in the way to be treated in Chapter II. 



