O r g a n i c C h e m i s t r y . Ethyl Fluoride. By H. MOISSAN (Conzpt. rend., 107, 260-263).-Ethyl iodide is allowed to drop gradually on to silver fluoride in a brass vessel, care being taken that the temperature does not rise too high. Any volatilised ethyl iodide is condensed by means of a fierpentine lead tube cooled to -20", and is allowed t o fall back upon the silver salt. The last traces of the iodide are removed from tho gas by passing it through two U-tubes containing silver

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... . I t is then collected in carefully dried glass vessels over mercury. Ethyl iodide in contact with excess of silver fluoride develops heat, and a gas is evolved, whilst a t the same time the yellow colour of the fluoride changes t o maroon. Under these conditions, a silver fluoriodide is formed, and this in contact with a fresh quantity of ethyl iodide at 100" yields silver iodide and ethyl fluoride. Ethyl fluoride is a colourless ~R S with an agreeable ethereal odour ; sp. gr. 1.70. It liquefies at -48" under normal pressure or under 8 atmos. at 19", and can be solidified by suddenly diminishing the pressure. It dissolves readily in several liquids. Water dissolves 1.98 vols. at 14"; ethyl iodide dissolves 14.8 vols. ; ethyl bromide, ether, and absolute alcohol especially, also dissolve large quantities. When the liquids are heated, the gas is completely expelled unaltered. Concentrated sulphuric acid also dissolves the gas. Ethyl fluoride burns with a blue flame which in presence of small quantities of methyl or ethyl chlorides becomes green. Admixture with a small quantity of oxygen produces a bright flame, and with a n excess of oxygen the gas explodes violently when ignited. When heated in sealed tubes at 100" with very dilute potash, ethyl fluoride is completely decomposed, and yields potassium fluoride, alcohol, and a large proportion of ether. Chlorine has no action on ethyl fluoride in the dark after severd hours, but gaseous fluorine completely and rapidly decomposes ethj I chloride. It follows that fluorine displaces chlorine from organic as well as inorganic compounds. Propylene Iodide from Ally1 Iodide and Hydrogen Iodide. By H. MALBOT (Compt. r e d . , 107,(113)(114)(115).-1t allyl iodide, cooled at -18", is treated with a regular current of hydrogen iodide, it yields propylene iodide ; but before combination is complete, the latter changes into isopropgl iodide without evolution of propylene. The change takes place slowly, but if the liquid i A treated with a further quantity of hydrogen iodide, the change becomes complete. If the allyl iodide is not cooled, the propylens iodide may decompose very violently : if it is heated, the propylene iodide decomposes as fast as it is formed. When the allyl iodide is mixed with isopropyl iodide, the decomposition of the propylene iodide takes place less rapidly, but still with considerable violence. This constitutes a convenient method for the preparation of propjlene. If allyl iodide 0. H. B.