840 COMPOUNDS CONTAINED IN WOOD TAR. 



pounds with potash ; one is anhydrous, liquid, of an oily consis- 

 tence, the other hydrated and crystallized in white pearly plates ; 

 they are both decomposed by all acids, even carbonic acid. It 

 mixes in all proportions with alcohol, ether, sulphuret of car- 

 bon, oil of petroleum and acetic ether. Creosote is remarkable 

 for dissolving a large number of organic colouring matters, 

 including cochineal, dragon's blood, litmus, madder, saffron, 

 and even indigo, when heated. It coagulates albumen, a pro- 

 perty upon which its corrosive action upon animal tissues may 

 depend. Butcher-meat or fish dipt in it, arid then exposed to 

 air, does not putrify,* but acquires the agreeable flavour of the 

 same kind of food when well smoked. 



Picamar (in pice amarum) is a transparent and nearly colour- 

 less liquid, of the consistence of an oil somewhat thickened ; its 

 odour is weak and peculiar, its taste insupportably bitter and 

 burning, then cooling, like that of peppermint. Its density is 

 1.10 at 68; its boiling point 518. It is the bitter principle, 

 according to M. Reichenbach, of all empyreumatic products. 

 It forms crystalline compounds with the alkalies and alkaline 

 earths, in which the latter are not neutralised. It is insoluble 

 in water, but soluble in alcohol and ether. 



Pittacal., a beautiful colouring matter, discovered by Reichen- 

 bach in the oil of tar ; the latter substance, when free from acid, 

 assuming a beautiful blue on the addition of barytes-water to it. 

 This substance when precipitated or obtained by evaporation 

 forms a deep blue mass, solid and friable, like indigo. It 

 assumes also a coppery lustre, like indigo, when rubbed. It 

 is inodorous, insipid and not volatile. Pittacal is insoluble in 

 water, but is suspended in that liquid in a state of such minute 

 division as to pass through a paper filter, and colour the 

 liquid blue. Its solution in acetic acid is of a rose red colour, 

 and recovers a very fine blue colour on the addition of an excess 

 of alkali. M. Reichenbach recommends it as a re-agent even 

 more sensible than litmus to the action of acids and alkalies. 

 It is not soluble in alcohol, ether or eupion. It is not altered 

 by air and light. 



Pittacal gives precipitates of a fine violet blue colour, with 

 acetate of lead, chloride of tin, ammoniacal sulphate of copper 

 and acetate of alumina. This substance may be available ulti- 



* Hence the name creosote, from Kptag flesh, and <row I save. 



