ACETATES AND THEIR MANUFACTURE. 293 



removed,, and the little effect produced is attained by a considerable 

 loss of salt which is absorbed by the animal charcoal. 



By disturbing crystallization by constant stirring during cooling 

 a nearly amorphous mass having the appearance of yellow wax is 

 obtained, which is much liked by many consumers. The product 

 thus obtained is not always a neutral salt, but sometimes a mix- 

 ture of neutral and basic salt (besides empyreumatic substances). 

 After cooling it must, therefore, be quickly and well packed in 

 order to protect it from the moisture and the carbonic acid of the 

 air. The sugar of lead solution may, however, also be evapo- 

 rated only so far that some mother-lye remains after cooling ; the 

 crystallized mass is then allowed to stand in a moderately warm 

 room for some time. In consequence of capillarity the impurities, 

 which occur chiefly in the inother-lye, gradually rise up between 

 the crystals, a slight coating of a yellow, or brown, smeary sub- 

 stance being finally formed upon the mass of crystals and can 

 be readily removed. 



The linen upon which the crystals are dried must be carefully 

 protected from fire, as it ignites from the slightest spark and burns 

 like tinder. 



If the hot solution be set aside to cool rapidly, the sugar of lead 

 crystallizes in clusters of fine needles ; but if the evaporation be 

 conducted slowly the crystals are truncated and flattened, quad- 

 rangular and hexahedral prisms derived from a right rhombic 

 prism. Acetate of lead has a sweet astringent taste, is soluble in 

 1J parts of water and in 8 parts of ordinary alcohol. The crys- 

 tals are permanent in the air, but are apt to effloresce and become 

 anhydrous if the temperature ranges between 70 and 100 F. 



Acetate of lead consists of 



Plumbic oxide ........ 58.9 



Anhydrous acetic acid . . . . . . ' 26.9 



Water ......... 14.2 



100.00 



Aqueous solution of sugar of lead slightly reddens litmus 

 paper, but shows an alkaline reaction upon turmeric, browning 

 this coloring substance. 



At 167 F. the crystals of acetate of lead melt, and but slowly 

 yield up their water ; by heating the entirely dephlegmated salt 



OF TH2 



7BR 



V C'jt _ *>* ^ W Ji 



