202 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



inflamiiiuble, and do not tarnish so easily. The specific grav- 

 ities are as follows: Cerium, 6.628 to 6.728; lanthanum, 6.049 

 to 6.163; didymium, 6.544. In their electrical relations the 

 three metals lie between magnesium and zinc ; they are elec- 

 tro-positive to the latter, electro-negative to the former. 

 Poggendorff^s Annalen, 3Iarch 25, 1875. 



EXPERIMENTS ON STEEL. 



MM. Treve and Durassier have communicated to the 

 French Academy the following results of their investiga- 

 tions into the relation existing between the chemical and 

 physical properties of steel. They j^repared fifteen bars of 

 steel, divided into five series of three bars, each series being 

 of a different degree of carburation, and each tempered in a 

 difierent manner. These bars Avere then magnetized to 

 saturation, and their magnetic force determined by the 

 method of deflection. The bar containing 0.95 per cent, of 

 carbon, and tempered with cold water, caused the maximum 

 of deflection, represented by 47. The bar containing the 

 same amount of carbon, but tempered with oil at 10 Centi- 

 grade (50 Fahr.), gave 43. That the magnetic capacity of 

 steel is influenced by the nature of the liquid used for tem- 

 pering seems therefore to be manifest. The bar containing 

 0.25 per cent, of carbon gave a deflection represented by 13, 

 showinsc how decided is the influence which it exerts. In 

 preparing diagrams of variations for the diflerent series of 

 bars, the influence of the percentage of carbon and of the 

 tempering liquid became manifest. It was remarked, how- 

 ever, that at the top of the scale in carbon, the nature of the 

 tempering liquid no longer exerted a very marked influence. 

 The study of these diagrams brought to light, likewise, the 

 noteworthy fact that a remarkable similarity existed be- 

 tween the magnetic curves and the curves of elasticity of 

 the bars. The investigators assert from their experimental 

 trials that carbon gives elasticity to the steel, and at the 

 same time enhances its capacity for magnetism. 3 ^,V., 556. 



INFLUENCE OF FOEEIGN INGREDIENTS UPON THE PHYSICAL 



PROPERTIES OF STEEL. * 



The experience that has of late been gained in the pro- 

 duction of phosphuretted steel may be characterized as a 



