We expect the amendment to enter into force in H2 2013.
Henry started with methyl iodide, the formula of which we write in the form CI a H b H c H d.
The same methyl iodide gave with potassium cyanide, acetonitril, which was hydrolysed to acetic acid; this must be C(Coch) a H b H c H d.
This acid with silver nitrite gave nitroacetic acid, which readily gave the second nitromethane, CH a (NO 2) b H c H d, identical with the first nitromethane.
Thus ethane gives H3C CH2 CH3, propane; ethylene gives H 2 C:CH CH 3, propylene; and acetylene gives HC: C CH 3, allylene.