130 M* Berthier on Forge Scales. [AxjGw 



Chlorine 90-743 



Boron 9*257 



nuoric acid, unless aided by nitric acid, neither oxidates 

 nor dissolves boron. 



It has been atfirmed that boron is dissolved in the dry way 

 by alkalies, and that when the fused mass is treated with water, 

 the boron is taken up by the alkaline liquid, and forms with it a 

 yellow coloured solution. This is incorrect. When boron is 

 Ignited with an alkaline carbonate, it detonates at the expence 

 of the carbonic acid ; and when it is ignited with the hydrate 

 of a fixed alkali, hydrogen gas is disengaged with effervescence, 

 and boracic acid is formed. 



In the properties which have now been brought under review, 

 boron possesses so close a resemblance to silicium, that the 

 two substances may be associated with one another, in the 

 same manner as we have been accustomed to associate arsenic 

 with phosphorus and selenium with sulphur. The affinities of 

 boron, however, are stronger, and in the lower temperatures, 

 more active than those of silicium ; thus, it detonates with 

 nitre in a low red heat with such energy, that the explosion 

 may be almost compared to that of gunpowder. 



{To })€ continued.) 



Article VIII. 

 On Forge Scales. By M. P. Berthier.* 



When pieces of iron are heated to whiteness, in order 

 to draw them out into bars, or roll them into plates, they be- 

 come covered with a coat of oxide, which flakes off in scales by 

 the blow of the hammer, or the pressure of the rollers. These 

 are called by the workmen forge scales. 



The thickness of the forge scales is proportionate to the time 

 that the masses of iron on which they are formed have remained 

 in the fire, but commonly it is from one to two miUimetres ; (from 

 rh) ^o tIo- of an inch) ; they are of a shining black colour, 

 with a semimetallic lustre ; their structure is crystalline and 

 presents intersecting laminae, perpendicular to the surface of the 

 scales. They are said to have been observed distinctly crystal- 

 lized, in regular octohedra. .,j,^ -i[. .-, 



They are usually composed of two parallel laminie, if\ie outer 

 one granular and blebby, the inner compact and "crystalline. 

 'This structure forbids a doubt of their being liquified at a cer- 



* From the Annnles de 



,%9^ 



