390 Mhcellaneoufi IiUeUigence. 



was decomposed by being boiled with excess of hydrate of 

 lime, which threw down all the oxide of copper, and formed an 

 acetate of lime; this was filtered, and carbonic acid passed 

 through the solution to separate any free lime dissolved in it ; 

 it was then heated, that the excess of carbonic acid and car- 

 bonate of lime might separate, and was then neutral acetate of 

 lime, containing the acetic acid of the verdigris. The lime was 

 then thrown down by carbonate of soda, and the carbonate of lime 

 ascertained, and the quantity of acetic acid in the verdigris de- 

 duced from its quantity; 63 of carbonate lime being considered 

 as equivalent to 63.96 of acetic acid. The quantity of oxide of 

 copper in the salt was ascertained by precipitating the salt with 

 potassa, and drying the precipitate. The water was deduced 

 from the loss of weight. In this way 100 of acetate of copper 

 appeared to be composed of 



Acetic acid .... 49.2 



Peroxide of copper . . . 39.2 



Water 11.6 



so that admitting peroxide of copper to be a compound of two 

 atoms oxygen 20, and one atom copper 80, the atomic corrSti- 

 tution of verdigris will be 



By Theory. By Experiment. 



2 atoms of acetic acid 127.92 128.84 

 1 atom of peroxide of copper 100. 102.65 



3 atoms of water . . 33.96 30.39 



261.88 261.88 



Mr. Phillips, in addition to Dr. Thomson's arguments for 

 concluding the sulphate of copper to be a bi-salt, states, that if 

 finely-divided carbonate of lime be added to a solution of it, 

 an effervescence takes place, and an insoluble sulphate of 

 copper falls. The same effect is produced by the soluble sul- 

 phate, nitrate, and acetate of copper, and hence Mr. P. is in- 

 clined to conclude that these also are bi-salts. — Annals of 

 Philosophy, i. 417. 



9. Analysis of Gun-Powder. — The usual mode of analyzing 

 gun-powder is to take a given weight of it well dried, to dissolve 

 out the nitre, to evaporate the solution and get the weight of 

 nitre, and to get the weight of charcoal and sulphur by drying 

 them together and weighing them. Another portion of gun- 

 powder is then taken and heated with as much potassa and a 

 little water, which dissolves out the nitre and sulphur, leaving 

 the charcoal, which, being washed and dried, is weighed. The 

 sulphur is estimated by the weight v;anted to complete the 

 sum of the weight of the nitre and charcoal. 



Another mode has been adopted in the laboratory, of the 

 direction of powders, which is shortly as follows. A certain 



