184 On Sulphuric Acid and Naphthaline. [1826. 



four parts by weight of cold sulphuric acid were put into a bottle, 

 well shaken, and left for thirty-six hours. The mixture then 

 contained a tenacious deep red fluid, and a crystalline solid; it 

 had no odour of sulphurous acid. Water being added, all the 

 liquid and part of the solid was dissolved ; a few fragments of 

 naphthaline were left, but the greater part was retained in 

 solution. The diluted fluid being filtered was of a light brown 

 tint, transparent, and of an acid and bitter taste. 



For the purpose of combining as much naphthaline as pos- 

 sible with the sulphuric acid, 700 grains with 520 grains of oil 

 of vitriol were warmed in a Florence flask until entirely fluid, 

 and were well shaken for about 30 minutes. The mixture was 

 red ; and the flask being covered up and left to cool, was found 

 after some hours to contain, at the bottom, a little brownish 

 fluid, strongly acid, the rest of the contents having solidified 

 into a highly crystalline mass. The cake was removed^ and 

 its lower surface having been cleaned, it was put into another 

 Florence flask with 300 grains more of naphthaline, the whole 

 melted and well shaken together, by which a uniform mixture 

 was obtained, but opake and dingy in colour. It was now 

 poured into glass tubes, in which it could be retained and ex- 

 amined without contact of air. In these the substance was 

 observed to divide into two portions, which could easily be 

 distinguished from each other, whilst both were retained in the 

 fluid state. The heavier portion was in the largest quantity ; 

 it was of a deep red colour, opake in tubes half an inch in 

 diameter, but in small tubes could be seen through by a candle, 

 or sunlight, and appeared perfectly clear. The upper portion 

 was also of a deep red colour, but clear, and far more trans- 

 parent than the lower: the line of separation very defined. 

 On cooling the tubes, the lighter substance first solidified, and 

 after some time the heavier substance also became solid. In 

 this state, whilst in the tube, they could with great difficulty 

 be distinguished from each other. 



These two substances were separated, and being put into 

 tubes, were further purified by being left in a state of repose 

 at temperatures above their fusing-points, so as to allow of 

 separation ; and when cold, the lower part of the lighter sub- 

 stance and the upper, as well as the lower part of the heavier 

 substance, were set aside for further purification. 



