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readily soluble in alcohol or ether, on evaporation of which it re- 

 mains behind as a thick oil. When boiled with water, it remains, as 

 far as can be seen, unchanged, Dilute solutions of the alkalies ap- 

 pear not to act on it. Heated with solution of ammonia, in a sealed 

 tube, at 100 C., it is decomposed, chloride of amonium and acrolein 

 ammonia being the result. It does not combine with bichloride of 

 platinum when in solution in alcohol, and very slowly reduces boiling 

 ammoniacal solution of nitrate of silver. Heated alone, it decom- 

 poses into acrolein and hydrochloric acid. By the action of concen- 

 trated hydrochloric acid acrolein is set free. Dilute sulphuric and 

 nitric acids decompose it likewise, setting acrolein free. Heated 

 with hydrate of potash it gives off hydrogen, and there distils at 

 the same time an oily body, which solidifies into magnificent colour- 

 less crystals, analyses of which prove it to be an isomeric acrolein, 

 for which the authors propose the name Metacrolein. 



Metacrolein as thus obtained is insoluble in water, but is capable of 

 being recrystallized from alcohol or ether. The crystals form very 

 long needles, more especially when melted metacrolein before solidify- 

 ing is allowed to flow about in a glass tube. They resemble very 

 much in appearance the crystals of acetamide, possess a peculiar 

 aromatic smell, and have a taste at first producing a cooling and 

 afterwards a burning sensation. They are lighter than water. They 

 melt at about 50 C., becoming solid at about 45C. Before melting 

 they are somewhat volatilizable, on which account they can be 

 distilled in the vapour of water. On being heated, metacrolein is 

 changed into common acrolein. Dilute alkalies do not effect any 

 change in this substance. By heating with mineral acids, common 

 acrolein is set free. On leading dry hydrochloric acid gas over 

 metacrolein in a bulb-tube, the metacrolein melts and combines with 

 the acid, producing the already-named hydrochlorate of acrolein. 

 From this behaviour, the authors believe the acrolein contained in the 

 combination of hydrochloric acid to be metacrolein, and not common 

 acrolein. If metacrolein be viewed as C 12 H 8 O 4 , the formula of the 

 hydrochloric acid compound would then be C 12 H a O 4 , 2HC1; and 

 the formation of metacrolein may be assumed to take place accord- 

 ing to the following equation, C 12 H 8 O 4 , 2HC1+2KOIIO=C 12 H 8 O 4 

 + 2KC1 + 4HO. The evolution of hydrogen has been found to be 

 the result of a secondary action. 



