136 Analysis of Birdlime. 



is converted into the malic and oxalic ocids. By continuing 

 the evaporation we obtain a yellow and very friable mailer, 

 which softens between the fingers like wax, possessing at 

 the same time a degree of elasticity, and melts with a gentle 

 heat. 



Potash combines with this matter, changes its yellow co- 

 lour to a brown, and forms with it a true soap. 



Alcohol dissolves it in part; forming a yellow solution, 

 ■which loses, its transparericy on the addition of water. 



If the alcohol be evaporated to dryness, a yellow substancp 

 remains, which has no longer a greasy appearance, and dif- 

 fuses an agreeable odour when burnt. 



Muriatic acid has no action on birdlime in the cold, but, 

 ■when heated* blackens it. 



Oxymuriatic acid, on the other hand, has a very different 

 and more powerful action on this substance. On passing 

 the gas through water containing liquefied birdlime, or by 

 shaking it in a flask along with very strong acid, we observe 

 the following phaenomena :-r-the birdlime speedily loses its 

 colour, becoming white ; it is now no longer viscid, and 

 separates into hard compact masses, which contain within 

 them a portion of the substance unaltered. This incom- 

 plete oxygenation may be ascribed, with great probability, 

 to the difficulty of preserving the birdlime liquid in hot wa^^ 

 ter, and the consequent obstacle to the action of the acid 

 beyond the external layer. 



The characters of oxygenated birdlime are: 1st, It may 

 be readily reduced to powder : 2d, It is insoluble in water 

 even when heated ; 3d, It refuses to melt at an elevated tem- 

 perature: 4th, It does not become yellow, or form resin, 

 when subjected to the action of the nitric acid. 



The acetous acid softens birdlime, and dissolves a certain 

 portion of it : the solution has a yellow colour and a nau- 

 seous taste: with the carbonate of potash it lets fall no pre- 

 cipitate : when evaporated it yields a matter which has the 

 properiies of a resin, but cannot be reduced to a state of 

 complete dryness. 



Some of the metallic oxides are readily reduced when 

 j:}eated with birdlime. 



The 



