300 DR T. H. ROWNEY ON THE 



increases in quantity. The oil at the same time becomes thicker, diminishes in 

 bulk, and Anally both oil and ammoniacal liquor become nearly solid. 



To purify the compounds, the pasty mass was collected upon a cloth filter, 

 washed with water, and then squeezed, to free it as much as possible from the 

 ammoniacal mother liquor. The squeezed mass was then dissolved in warm al- 

 cohol, and allowed to crystallize, again filtered through cloth, and washed, first 

 with dilute alcohol (made with equal parts of alcohol and water), then with wa- 

 ter, and the residue again expressed ; and this was repeated until it was obtained 

 free from a resinous matter which adheres obstinately to it. When pure, these 

 amides are perfectly white, and undergo no change by exposure to the air ; but 

 if any of the resinous matter adheres to them, they speedily change colour, be- 

 coming yellow and resinous. The alcoholic mother liquors from which they have 

 been crystallized retain a considerable quantity of the substances dissolved in 

 them, which may be separated by the addition of water. 



The original ammoniacal fluids, when evaporated on a water-bath, yield a 

 considerable quantity of a dark oily or resinous matter, mixed with some of the 

 amide. 



The quantity of the crystalline compound obtained from each oil varied very 

 much, some yielding a considerable, and others a very small quantity. The time 

 required for the completion of the action also differs ; with some the change is 

 readily and rapidly effected, but with others, and particularly with the drying 

 oils, long-continued digestion is required. The latter oils yield a very small pro- 

 portion of the crystalline compound, but a considerable quantity of resinous mat- 

 ter is obtained by evaporating the ammoniacal mother liquors. 



The quantities of substance employed for analysis were dried in vacuo over 

 sulphuric acid, and the combustions were made with chromate of lead. The ni- 

 trogen determinations were principally made by Mr Mitchell's modification of 

 Peligot's method, viz., caustic soda, to neutralize the excess of sulphuric acid, 

 infusion of logwood being used as the colouring matter. 



The fusing point was taken by placing a small quantity of the substance in a 

 thin glass tube suspended in water contained in a metal vessel, which was heated 

 by a gas flame, and the temperature ascertained by immersing a thermometer in 

 the water. When the fusing point was found, the gas flame was removed, the 

 water allowed to cool, and the temperature at which solidification took place was 

 also observed. In the case of the amide which fused at 103° C, common salt 

 was added, in small quantities at a time, so as to raise the temperature gradually 

 until the fusing point was obtained. 



The following are the oils that I have already examined, and several others 

 are in course of examination. 



Almond oil, linseed oil, poppy oil, cod-liver oil, seal oil, and croton oil ; also 

 almond oil and castor oil, after solidification by nitrous acid. 



