of Edinburgh, Session 1877-78. 
591 
an upright condenser, precisely in the same manner as the first. In 
this second flask it is practically entirely decomposed. The C 2 H 2 
is then passed through alcohol at 0° (to absorb traces of C 2 H 3 Br), 
then through two Wollf’s bottles filled with water, and lastly through 
two CaCl 2 tubes. The gas may then be considered practically pure. 
To test this, I passed it for about half an hour through the two 
weighed flasks, surrounded by a mixture of ice and salt, but at the 
end of that time they had not gained in weight to speak of. 
To prepare first cuproso vinyl oxide-— 
C 4 Cu 4 H 2 0 ( Berthelot .) 
and then decompose this by dilute hydrochloric acid, is an extremely 
tedious and troublesome operation, and offers very little corre- 
sponding advantage. Sabanjeff discusses the other known methods 
for the preparation of C 2 H 2 very fully in his paper. I also tried 
some of them, but found the above by far the best of all. 
Action of Acetylene (C 2 H 2 ) on IC1 3 . 
On passing C 2 H 2 over pure dry IC1 3 at 0°, combination takes 
place with great evolution of heat. I always found more or less 
iodine separated out. My chief object being to try to prepare the 
compound, C 2 II 2 C1I, I did not investigate farther the products 
formed. Probably, if the IC1 3 were kept cold in a mixture of ice 
and salt, and the C 2 H 2 diluted with air and passed over it very 
slowly, one might get the compound C 2 H 2 C1 3 I. 
Action of C 2 H 2 on IC1. 
(a.) On pure IC1 at 0°. 
The evolution of heat produced by the combination was so great 
that more or less iodine always separated out. 
( b .) On IC1 dissolved in excess of ether at 0°. 
The ether used must be perfectly free from alcohol and water. 
The C 2 H 2 was passed as quickly as possible through this ethereal 
solution, to reduce as much as might be the secondary reaction of 
the IC1 on the ether. It was absorbed greedily. 
After saturation the ethereal solution was diluted with water, 
when a heavy liquid settled to the bottom. This was washed with 
dilute NaOH solution, and then with water, and dried over CaCl 2 . 
