24 Mr. Faraday on the 



contain no nitrogen, liave been tried with potash in tubes open to 

 the air ; lignine, prepared by boiling linen in weak solution of pot- 

 ash, then in water, afterwards in weak acid, and finally in water 

 again ; oxalate of potassa, oxalate of lime, tartrate of lead, 

 acetate of lime, asphaltum, gave very striking quantities to tumeric 

 and litmus paper ; acetate of potash, acetate of lead, tartrate of 

 potash, benzoate of potash, oxalate of lead, sugar, wax, olive 

 oil, naphthaline, produced ammonia, but in smaller quantity : resin 

 appeared to yield none, nor when potash was heated in the vapour 

 of alcohol or ether, or in olefiant gas, could any ammonia be de- 

 tected. 



It may be remarked, that much appeared to depend upon the 

 quantity of potash used; sugar, for instance, which with a little 

 potash would with difficulty yield traces of ammonia, does so very 

 readily when the quantity of potash is doubled or trebled ; and 

 linen, which with potash gives ammonia very readily, yields it the 

 more readily, and in greater quantity, as the proportion of potash 

 is increased. 



The experiments with the substances which contain carbon, assi- 

 milate, in consequence of the presence of that body, with the one 

 by Mr. Woodhouse. Whether the substances act exactly as char- 

 coal does, probably, cannot be decided until the correct nature of 

 the action is ascertained ; but there are apparently some very evi- 

 dent differences. The ammonia, in the charcoal experiment, does 

 not exist until after the ignition, nor before the addition of water; 

 but in several experiments of the nature of those described in this 

 paper, the ammonia is evolved before the substances acting or 

 acted upon, are charred. Thus, if linen fibre, cut small, be mixed 

 in the tube with hydrate of lime, and heated, ammonia is evolved 

 before the heat has risen so high as to render the linen more than 

 slightly brown ; and oxalate of potash, in a tube with potash, 

 when heated, gives much ammonia before any blackening is pro- 

 duced. 



Mr. Woodhouse's experiment may be very readily repeated, 

 though not in an exact way, by heating a little tartrate of lead 

 with potash, in a tube in the flame of a spirit lamp, driving off th^ 



