1835.] Improvements in Science. 117 



much paraphosphoric acid as will saturate the two oxides. 

 Ammonia is poured in, which forms a precipitate re-dis- 

 solved by an excess of ammonia, and the liquid becomes 

 violet coloured. When allowed to stand the excess of alkali 

 flies off, and the solution becomes turbid in consequence of 

 the deposition of ammonia paraphosphate of nickel, which 

 at first possesses a greyish colour, but ultimately becomes 

 green. When the precipitate completely subsides, the rose 

 coloured supernatant liquor is drawn off, which, if it con- 

 tains no more nickel, may be evaporated to the consistence 

 of a syrup. The paraphosphoric acid may be separated from 

 the oxides by carbonate of soda. 



Separation of Oxide of Cadmium from Oxide of Bismuth. — 

 Persoz has observed that the paraphosphate of bismuth is 

 insoluble in ammonia, and that the paraphosphate of cad- 

 mium is very insoluble. Hence, this is a ready method of 

 separating the two oxides. He prepares the acid by calcin- 

 ing pure phosphate of ammonia. 



Separation of Oxide of Uranium from the Oxide of Cobalt, 

 Nickel, and Zinc. — The subacetate of lead separates the 

 oxide of uranium from the other three oxides, for a solution 

 of this salt poured into a solution of uranium in nitric acid, 

 occasions a precipitation of uraniate of lead, the other oxides 

 present not being affected. 



Manufacture of the Tarn Tarn and Cymbals of the Chinese, 

 (Ann de Chim. liv. 329.) — According to M. Stanislaus Julien, 

 the Chinese in the formation of the tam-tam, run the alloy 

 into leaves, and then fashion it in the proper way; but 

 according to Darcet this is impossible, because the alloy is 

 as brittle as unanealed glass. The tam-tam and cymbals 

 consist of 



Tin ... . 0-20 

 Copper . . 80 



100 

 The most probable mode of manufacture appears to be 

 by running a piece modelled in sand in a font with the 

 alloy. The piece taken from the mould is finished off, and 

 tempered like steel. If it is distorted by being plunged 

 while hot into cold water, the injury is rectified by a ham- 

 mer. The tone appears to be given either by the tempering 



