398 Proceedings of the British Association. 



termed by Dr Dalton bin-olefiant gas. This is proved by its 

 affording twice the quantity of carbonic acitl, and requiring 

 twice the quantity of oxygen to burn it which defiant gas re- 

 quires. Mr W he well observed, that the atoms might as well 

 be supposed to be arranged in lines, as in the mode represented 

 by Dalton, which was objected to by the latter, as being a tot- 

 tering equilibrium. 



20. Mr Mallet shewed a beautiful white material, prepared 

 from turf, which was declared by a paper- maker to be perfectly 

 fitted for the manufacture of paper. The upper stratum of 

 turf, which covers immense tracts in Ireland, consists of layers. 

 It is acted on by water to separate the leaves ; then by caustic 

 potash or soda; then by an acid. It is then bleached by chlo- 

 ride of lime. During the process, a substance is obtained pos- 

 sessing the odour of camphor, mixed with that of turpentine, 

 which is fluid at 290° F. The upper stratum of turf may also 

 be employed for mill-hoards, after being soaked in glue and 

 pressed by a hydraulic press. 



Friday, \^th August. — 21. Mr Davy described some experi- 

 ments which he had made in reference to the relative values of 

 Virginian and Irish tobacco. He procured nicotine by simply 

 digesting the leaves in potash, and then distilling. A liquid 

 possessing uniform qualities passed over. The liquid is acted 

 on by acids, affording salts possessing a sharp biting taste. The 

 effect of the liquid was tried upon different animals, and found 

 to be highly narcotic. He found that 1 lb. of Virginian tobac- 

 co was equivalent to of Irish tobacco ; the root containing 

 4 or 5 per cent, of nicotine. The usual estimate of the relative 

 values, by dealers, is as 1 to % 



Mr Scanlan detailed the experiments which he had made 

 upon what he considered a new fluid, prepared from pyroiig- 

 nous acid by saturation with lime, distillation and purification 

 by charcoal. He found its boiling point to remain steady at 

 130°. The following table exhibits its peculiarities when com- 

 pared with pyro-acetic and pyroxylic spirits. 



Sp. Gr. Boiling Point. 



Pyro-acetic, .... .828 • 150° 



Pyroxylic, 750 140° 



New Fluid, 906 130 



Another fluid was obtained likewise, which appeared to be new, 



