OF THE PARA-FFINS AND THEIR MOHOHALOGEH DERIVATIVES. 
17 
The results of the remaining two experiments made on methane prepared by Glad¬ 
stone and Tribe’s method are given in the second and third line of Table II., with 
the temperature, the ratio of semi-contraction to CO^, and the percentage of air. 
The next three experiments were made on marsh gas got by the action of zinc 
methyl on water. 
This method is not attractive from the offensive nature of the zinc compound and 
the violence of its reaction with water, but it gives a pure product. 
The zinc-methyl was made by digesting methyl iodide with a copper-zinc couple on 
the water bath, and distilling off the product on an oil bath. 
The reaction was very complete, the contents of the flask after the first operafion 
being quite dry on cooling, but to ensure the removal of any unaltered methyl iodide 
a stream of carbonic acid was passed through the flask for some time whilst it was 
kept at 100°. 
In the final distillation the end of the condenser dipped below the surface of dry 
ether cooled in ice, by means of which loss was prevented and an almost theoretical 
yield obtained. 
The principal reason for mixing the zinc-methyl with ether will be detailed at 
length in the description of the preparation of ethane, which was the first gas 
investigated. What is said there will in all probability apply with even greater 
force here, where the compound is more easily dissociated, and the reaction more 
violent. The addition of ether adds very much to the comfort of the experiment, for 
the mixture can be poured from one vessel to another without any greater incon¬ 
venience than strong fuming. 
To prepare the methane the mixture of ether and zinc-methyl was dropped slowly 
into a flask containing distilled water and the gas evolved collected without 
purification over boiled water, with which it was shaken to remove as much ether as 
possible. 
It was passed into the Kundt apparatus through two sets of Geissler bulbs of 
strong sulphuric acid to remove the ether and traces of methyl iodide, one of potash 
to absorb any sulphur dioxide formed in the first two, and another of sulphuric acid 
to dry it. After this treatment it issued without smell. 
In experiment IV. the potash was by mistake omitted, and the consequence was 
that the gas was found to contain '5 per cent, of sulphur dioxide. 
The results of the three experiments are shown in lines III., lY., and V., of 
Table II. 
MDCCCXCIV.—A. 
D 
