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XXVII. Researches on a New Class of Alcohols. 
By Augustus Williajvi Hofmai^n, LL.B., F.R.S., and Augustus Cahoubs, F.C.8. 
Received May 15, — Read June 18, 1857. 
On submitting glycerin to destructive distillation, either alone or in the presence of 
bisulphate of potassium or anhydrous phosphoric acid, a very remarkable product is 
obtained, which has been elaborately studied by Professor Redtenbachee. 
According to the researches of this distinguished chemist, this substance, to which 
the name of acrolein has been given, presents all the characters of an aldehyde, and 
bears, in its reactions, a close resemblance to the vinic aldehyde. Under the influence 
of oxidizing agents, and especially of oxide of silver, this body changes into an acid 
which Redtenbachee designates by the name “ Acrylic Acid,” and which stands to acro- 
lein in the same relation that acetic acid bears to common aldehyde. 
The researches of MM. Will and Weetheim upon the volatile oils of garlic and 
mustard established a relationship between these compounds and acrolein which has 
been rendered still more evident by the recent investigations of MM. Beethelot and 
De Luca. 
In studying the action of iodide of phosphorus upon glycerin, these chemists obtained 
a volatile liquid containing iodine, the composition of which is expressed by the formula 
Cg Hj I, and to which they appHed the name Iodide of propylene. 
This substance is evidently allied to the chloride of propylene, Cg Hj Cl, and bromide 
of propylene, Cg Hj Br, discovered previously by Cahoues, Reynolds and Hofmann, in 
studying the action of chlorine and bromine on the gases which are obtained by sub- 
mitting either amylic alcohol or valeric acid, as well as their higher homologues, to the 
action of heat. 
A glance at the formul® of the propylene-compounds, and the volatile oils of garlic 
and mustard, viz. 
Chloride of propylene . . . Cg Hj Cl, 
Bromide of propylene . . . Cg Hj Br, 
Iodide of propylene . . . . Cg Hj I, 
Garlic oil Cg S, 
Mustard oil Cg Hg C^ NSg, 
obviously shows that the same radical Allyl, Cg Hg, may be assumed to exist in all 
these compounds. 
This relation did not escape Reynolds, who, in his memoir pubhshed about six years 
