132 SCIENTIFIC AMUSEMENTS. 



formed, and all the copper will be removed from solution; when 

 this is the case take out the key, and divide the fluid into two 

 equal parts ; to one half add a dessertspoonful of strong solution 

 of ammonia; a muddy brownish light-green copious precipitate 

 will be formed, but no blue solution ; whilst the original solution 

 of chloride of copper similarly treated will give a beautiful deep 

 blue fluid. To the other half add some solution otferricyanide 

 of potassium (red prussiate of potash), when a deep blue precipitate 

 of "Turnbull's blue" (Expt. 83) will form; whilst the original 

 copper chloride solution will give a yellowish-green coloured pre- 

 cipitate with the same test. N. B. Neither of these two tests for 

 iron Avill work satisfactorily unless the key has remained in the 

 liquid long enough to precipitate all the copper from solution. 



Expt. 133. To make a Lead Tree or "Arbor Saturn!" Get a 

 good-sized wide-mouthed glass jar or small fish-globe, and fill it full 

 of a solution of sugar of lead made by dissolving that salt in hot 

 water in the proportion of about an ounce of the salt to between 1 

 and 2 pints of water; let the solution stand twenty-four hours to 

 settle before use, pouring off only the clear fluid free from sedi- 

 ment into the jar. Now get some lumps of zinc (not too thin) 

 weighing altogether two or three times as much as the sugar of 

 lead used; tie them together with string or copper wire, or fix 

 them to a wooden or wire frame here and there over its surface. 

 Suspend the bunch by means of a string from a stick laid hori- 

 zontally over the mouth of the jar (like the bell-dialyser in fig. 54), 

 so that the lumps of zinc are all immersed in the sugar of lead 

 solution, which should nearly fill the jar. After a few hours the 

 zinc will have "displaced" the lead from the solution, just as the 

 iron did the copper in the previous experiment; as the lead 

 deposits it forms bright glistening feathery plates and films hanging- 

 down from the zinc, and altogether forming, if rightly managed, 

 a beautiful metallic tree, which will remain permanent for a long 

 time if kept immersed in the liquid, and not roughly handled or 

 shaken so as to dislodge the delicate crystals of lead from their 

 support. If, however, you attempt to remove the tree from the 

 fluid, you will probably spoil it entirely. 



Expt. 134. To make a Silver Tree or "Arbor Dianse." 

 Many other instances of this kind of chemical action are known, 

 especially amongst metals. A solution of nitrate of silver into 

 which a teaspoonful of mercury is dropped, will on standing form 

 a " silver tree " or " arbor Diana3," * consisting of crystals of silver 



* Diana and Luna were two alchemical names for silver, as was also 

 Saturn for lead, Jupiter for tin, Mars for iron, and Venus for copper, and so 

 on with the other planets 



