386 



Miscellaneous hitelligence. 



following table up to eight atmospheres, as nearly correct : above 

 that they say it was impossible to go without farther experiments. 



of the fusible plugs or plates, but their preparation intrusted to 

 some competent person who should be responsible for the accuracy 

 of their fusing points. The fittest place tor them, all things being 

 considered, is the upper surface of the boiler. Their proper 

 diameter and thickness have not yet been ascertained ; they should 

 be such as to bear the force of the vapour without risk of 

 breaking ; and when the plate is fused, to leave an aperture sufficient 

 for the ready escape of the vapour. — Ann. de Chimie, xxvii. 95. 



8. Preparation of Dmnasked Steel. — M. Breant has been engaged 

 in numerous series of experiments on the production of steel of 

 various qualities, and particularly damasked, like that of which the 

 oriental blades are made ; and the conclusion he has arrived at, is, 

 that the damask is produced, not by welding together wires and 

 rods of steel, and twisting them in various directions, but by using 

 a fused or cast steel more carburetted than the steels of Europe ; 

 and in which, by the effect of slow cooling, a separate crystalliza- 

 tion of two distinct combinations of iron and carbon has been 

 eflected, which separation is the essential condition to the pro- 

 duction of a damask. 



If iron be united to a small proportion of carbon, insufficient to 

 convert the whole into steel, and the fused mass be cooled slowly, 

 the steel and the iron will partly separate from each other, and the 

 metal will, when properly treated, exhibit a white damask. A 

 further proportion of carbon will convert the whole into steel, which, 

 when solid, will not exhibit any appearance of separation among its 



