119 



method of the variation of parameters, proper for determining 

 directly the motion of the apses of an orbit. 



III. " On some of the Products of the Distillation of Boghead 

 Coal at low temperatures." By C. GEEVILLE WILLIAMS, 

 Esq., Assistant to Dr. ANDERSON, Professor of Chemistry 

 in the University of Glasgow. Communicated by Dr. 

 SHAREEY, Sec. E.S. Received May 14, 1856. 



In presenting a brief preliminary notice of an investigation of the 

 substances obtained by distilling boghead coal at low temperatures, I 

 may observe that J was induced to undertake it from remarking the 

 low density of the naphtha produced in the process ; it being only 

 "750 at 60 F., although its boiling-point, previous to the rectifica- 

 tions, was as high as 290 F. 



After fifteen complete fractionations of the portion distilling below 

 3LO F., boiling-points were obtained as low as 170, and it was 

 found that the fluid could be separated, by careful treatment with 

 fuming nitric, or a mixture of nitric and sulphuric acids, into two 

 bodies, one forming a nitro-compound, the other being unacted on. 

 The latter was washed several times with a strong alkaline solution, 

 and, after being digested for a few days with sticks of potash to 

 remove adherent moisture, rectified over sodium. In this manner I 

 obtained a colourless and very mobile fluid with a pleasant odour, 

 distantly resembling that of hawthorn blossoms. Its density at 60 

 was '725. 



I selected the fraction boiling in the fifteenth rectification at 

 240 F. to make a preliminary experiment upon, and, after purifica- 

 tion in the manner described, it gave in three perfectly concordant 

 analyses, exactly the per-centage of carbon and hydrogen required 

 for butyl (valyl of Kolbe), the radical of the butylic alcohol. Two 

 determinations of the vapour density, taken respectively at 80 and 

 107 above its boiling-point, gave numbers closely coinciding with 

 theory. 



When it is considered that 68 or more of difference of boiling- 

 point only cause a variation of 0-3 in the per-ccntage of carbon and 

 hydrogen of bodies of this class, it becomes evident that if I had 



M 2 



