433 



tion of paralysis-layers is altogether excluded; but the part the 

 oxygen has played in om experiments, gives but little hope that 

 we shall be enabled to fulfil this condition in the near future. 



§ 3. On examining the graphic representations we notice especi- 

 ally in those hydrations with gas- mixtures deficient in oxygen, a 

 strong curved line, pointing to paralysis. This paralysis evidentlj' 

 enters sooner with the cinnamic acid aethylester than with the 

 methylester, moreover part of the catalyser repeatedly flocked out. 



To make the phenomenon stand out the more, we at first added 

 somewhat less Pd-sol. 



With N". 23 we first used 2 ccm. ; after 30' another 3 ccm. 

 were added. Though the velocity after the second addition was very 

 considerable, yet a strong retardation soon set in. 



When starting from 1 ccm. sol, the velocity had soon decreased 

 to zero, but when a second ccm. sol was added, the initial velocity 

 was of a similar order of magnitude and occasionally even some- 

 what greater than if we had immediately started from 2 ccm. sol. 



With a view to the ever varying quantity of oxygen we must 

 be very cautious in drawing a conclusion. But it may be in indubitably 

 concluded that the paralysis of the first quantity of sol does not 

 happen to the same extent, as otherwise hardly any hydration would 

 have set in. The first quantity of sol will probably fix an impurity 

 of unknown nature ; perhaps the second quantity can partially take 

 on the paralysing substance from the first quantity. A closer in- 

 vestigation is desirable. 



§ 4. With the undecylenic aethylester too, a great retardation in 

 the second part of the hydration had been observed, during the first 

 experiments. (N". 4 — 7, without thermostat). 



The same took place with the undecylenic acid when using H, 

 freed from oxygen, 2.0237 gr. dissolved in 100 ccm. 80 7o 

 alcohol -|- 4 ccm. Pd-sol, employed 252,5 ccm. calculated 253 ccm. 

 (N°. 30). 



The first 130 ccm. were absorbed in 5 minutes, then a very 

 pronounced retardation set in, in the following 5 min. 24 ccm. 

 were absorbed and in the then succeeding 5 min. 16 etc. 



Simultaneously a flocking-out had set in, which proved to be com- 

 plete when the reduction was over. 



As a solution of undecylenic acid -|- 4 ccm. Pd-sol remained 

 unchanged for days, it may consequently be ascribed either to the 

 undecylenic acid formed, to the reduction itself, or to both. 



