112 EEPORT— 1891. 



a trace of organic matter, probably higher hydrocarbons. The 

 reaction was evidently, therefore, principally as follows : — 



Mg + 2EtI = Mgia + C2H4 + C^Hg. 



As the escaping gas was not analysed, it is not known 

 whether it was a mixture of ethylene and ethane, or an equi- 

 valent amount of other hydrocarbons. 



Experiment II. 



The success of Gladstone and Tribe with zinc-copper 

 couples in the production of zinc ethyl (Journ. Chem. Soc, 

 xxxi., p. 567), led me to try this and the following experi- 

 ment. The copper appears to take no active part in the re- 

 actions, except as playing the part of the negative plate in a 

 galvanic cell. 



Five grams of magnesium-filings were treated with sufiicient 

 of a 2-per-cent. solution of copper sulphate, rendered alkaline 

 with ammonia, to yield 0-35 gram of metallic copper. As soon 

 as the copper solution was decolorised (which took but one or 

 two minutes), the couple, which acted on water with great 

 energy, was washed rapidly with water, then with alcohol, 

 and finally with anhydrous ether. It was next dried by heat- 

 ing in a current of hydrogen in the flask of the distilling 

 apparatus, which was then attached to the condenser. When 

 the apparatus was full of hydrogen, 20 grams of ethyl iodide 

 were run in. As in I., there was no action in the cold. The 

 flask was heated in a water-bath to about 90° for ten hours, 

 when the condenser was reversed ; but nothing except a little 

 ethyl iodide came over. More ethyl iodide containing a little 

 iodine in solution, as recommended by Frauklandin the manu- 

 facture of zinc ethyl (Eoscoe and Schorlemmer, iii., i., p. 460), 

 was added ; and the heat was kept up for a further period of 

 twenty-five hours. The colour of the iodine was only slowly 

 removed by the magnesium, which agrees with Wanklyn's ob- 

 servation (Journ. Chem. Soc, xix., p. 144). A white solid was 

 formed, as in I. The condenser was again reversed, and the 

 flask heated in an oil-bath, when a small quantity of ethyl 

 iodide came over. The receiver was then changed. When the 

 inner thermometer was rising from 100° to 120°, a few oily drops 

 distilled over, which were not increased, although the oil-bath 

 went up to 250°, and the inner thermometer registered 170°. 

 These drops volatilised in the current of hydrogen, producing 

 a somewhat alliaceous smell, which nevertheless strongly 

 reminded one of kerosene. This agrees with Hallwachs and 

 Schafarik's account ; but, on the other hand, there was no 

 fuming on disconnecting the apparatus. The reaction was 

 apparently the same as in I., the residue being the same, with 

 the addition of the metallic copper. 



