000 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



small quantity could be obtained in solution, so that the pre- 

 pared bath could not be operated with for any length of 

 time. He therefore recommends the preparation of a bath, 

 by treating at the boiling temperature any desired quantity 

 of freshly precipitated platin- ammonium chloride with a 

 saturated solution of citrate of soda. The result is the im- 

 mediate formation of a deep orange- colored solution, very 

 rich in platinum, which will afford, with two Bunsen cells, 

 a handsome, homogeneous, and tenacious platinum coating. 

 Gaiffe has likewise recommended the use of a cobalt plating, 

 obtained by galvanic means with a neutral solution of double 

 sulphate of cobalt and ammonia, for its hardness and beauty, 

 as a protective coating for plates used in copper-plate engrav- 

 ings. 



The disaggregation of metallic tin is a curious phenomenon 

 to which the attention of metallurgists was prominently drawn 

 last year by the publicity given abroad to several remarkable 

 cases where it had been noticed. The fact appears to be es- 

 tablished that for some reason, at present quite unintelligi- 

 ble, metallic tin will at times become so granular and friable 

 that it may readily be crumbled between the fingers. This 

 disintegration cannot be ascribed to any impurity that the 

 metal contains, since it has been noticed to occur with metal 

 containing only traces (0.3 per cent.) of foreign metals, no 

 sulphur or phosphorus, and no oxide. It has been observed 

 to occur in organ-pipes, but cannot be ascribed to the effect 

 of vibration, as in other cases (and the recent cases referred 

 to) it has occurred in tin that had been stored in warehouses, 

 at a tolerably uniform temperature, and untouched for some 

 time. 



The influence of carburation upon nickel has been studied 

 by Boussingault with the view of ascertaining whether such 

 carburation would affect it like iron, and also to ascertain 

 whether its combination with steel would render the latter 

 less oxidizable. His results showed that while he was able 

 to carburize nickel as readily as iron, the metal showed no 

 increase in elasticity, hardness, and tensile strength. It did 

 not possess the property of tempering, and the alloy with iron 

 rusted easily unless the same contained a large percentage of 

 nickel. 



