284 ODORorxiiAPiiiA. 



acids, and be very detrimental to the true odour of the product 

 required.* 



Valrral, or Valerianic aldehyde, C. H ^^ 0. Allow a mixture 

 of 11 parts amyl alcohol, 16 J parts sulphuric acid and 16 J parts 

 water to flow slowly into a lukewarm solution of 12 J parts 

 potassium dichromate, whereby sufficient heat is produced to 

 cause the greater part of the valeral to distil over ; towards the 

 end, however, the distillation must be assisted by external heating. 

 The oily layer of the distillate is separated and shaken up, first 

 with potash-ley, to remove valerianic acid formed at the same time, 

 and then with acid sodium sulphite, with which it forms a 

 crystalline compound. The resulting crystals are pressed and 

 washed with alcohol and the valeral is separated therefrom by 

 distillation with sodium carbonate. It is a colourless, very mobile, 

 strongly refracting liquid, having a burnhig, bitter taste and 

 pungent, fruity odour, exciting coughing when inhaled (as do 

 many of the amyl compounds). Its sp. gr. is 0-8057 at 17^ C. 

 and 0-8224 at 0^ C. ; boiling point 96^-97^ C. under ordinary 

 pressure; 92^-8 under a pressure of 740 m. m. (Kopp.). It 

 is very inflannnable, burning with a bright flame. Insoluble in 

 water, but mixes in all its proportions in alcohol and volatile 

 oils. 



* Fusel Oil is an offensive strong-smelling oil, produced along Avith alcohol, 

 during the fermentation of grain, potatoes, etc., on the large scale, and "svliich 

 gives the peculiar and disagreeable flavour and odour to raw whiskey. It is 

 found chiefly in the last portion of the spirit which passes over, called the 

 " faints," to which it imparts its characteristic odour and flavour. By rectifying 

 the faints at a very gentle heat, most of the alcohol and water first pass over 

 together with only a little fusel oil, whilst the latter forms the residuum in the 

 .still. Various names are given to the crude oil thus obtained, according to its 

 source. In each case it essentially consists of hydrated oxide of amyl, but 

 trifling and variable quantities of other organic compounds are mixed with it, 

 M'hich slightly modify its character, more particularly its odour and flavour. 

 The Oil of potato spirit is the purest form of crude fusel oil. It is a nearly 

 colourless, volatile liquid, with a rather high l)oiling point, a durable, 

 penetrating, ottensive smell, and an acrid, burning taste. It may be purified 

 by the following process : — Introduce the ordinarj^ fusel oil of the distilleries 

 into a small still or retort, connected with a condenser, and apply heat ; as soon 

 as the oil begins to flow over unmixed with water, the receiver should be 

 changed and the distillation resumed and carried nearly to dryness ; the jjroduct 

 in the second receiver, and the matter which separates from the water in the 

 first receiver, are to be reserved for use in the preparation of valerianate of 

 soda, etc. 



