229 



The results which M. Cloez has obtained in the analysis of the 

 hydrochlorate are not less in favour of my views. He finds 1'28 per 

 cent, of hydrogen more than required by his formula, whilst ad- 

 mitting my theory, he would not have lost more than 0*13 per 

 cent. 



I have since examined several other salts of ethylene-diamine, and 

 the results fully confirm the conclusions drawn from my former 

 analyses. It would be useless to quote these additional experiments, 

 but I will mention the characteristic numbers furnished by the ana- 

 lysis of the anhydrous base, since the diminution of the equivalent 

 exhibits in a more striking manner the differences between the 

 theoretical values of the two formulae. Ethylene-diamine retains the 

 water with the greatest energy, and it is in fact only by protracted 

 contact with metallic sodium that it is possible to obtain this body 

 in the anhydrous condition. I give the numbers obtained by com- 

 bustion, side by side with the theoretical values of the two formulae : 



Analysis. 



40-13 

 13-31 



These numbers require no commentary. 



It is not, however, in the results of analysis that M. Cloez finds 

 the chief support of his views ; he quotes an observation which at the 

 first glance appears fatal to the diatomic notions. 



" But there is," continues M. Cloez, " a capital fact (un fait 

 capital) which completely settles the question at issue : this is the. 

 vapour-density of the free base" 



This density has been found by experiment to be 1'42. 



" The theoretical density calculated for my formula, referred to 

 4 volumes, is 1*315 ; the modified formula of M. Hofmann, likewise 

 referred to 4 volumes, gives the theoretical density of 2' 699. 



" These results appear to me decisive, and I do not hesitate to 

 maintain the formula of the new series of bases, of which I first 

 pointed out the formation." 



I entirely agree with M. Cloez as to the importance of the deter- 

 mination of the vapour-densities, but I certainly arrive at a very 

 different interpretation of his result. 



R2 



