280 ANNUAL OF SCIENTIFIC DISCOVERY. 







upon by one hundred grammes of sodium has yielded forty-five grammes of 



magnesium. 



The crude magnesium is introduced into a hallow vessel coated with 

 charcoal, and this again is placed in a tubs likewise coated with charcoal, 

 and the whole brought to a lively red, almost white, heat, while a stream 

 of hydrogen gas is made to pass slowly through the tube, which is in- 

 clined downwards in the furnace ; all the magnesium condenses just be- 

 yond the hollow vessel, and is gathered easily when the tube is cold. It 

 is afterwards fused in a mixture of the chlorides of magnesium and fluoride 

 of calcium. 



In distilling magnesium, if the current of hydrogen is too strong, a little 

 metallic, powder is carried out of the apparatus along with the hydrogen 

 gas. If this is ignited, it burns with one of the most beautiful flames it is 

 possible to imagine, and this experiment would make a charming exhibition 

 for a lecture room. 



PREPARATION AND PROPERTIES OF METALLIC MANGANESE. 



Brunner has recently published the following results of an investigation 

 of the properties and preparation of the metal manganese : 



The reduction of manganese is obtained as follows : An earthen crucible 

 (a Hessian one) is half filled with alternate layers of fluoride of manganese 

 and of metallic sodium, cut into plates from one to two lines in thickness, 

 in the propoi'tion of two parts of the former to one part of the latter by 

 weight ; the whole is then gently tapped, in order to leave as few inter- 

 stices as possible, and covered with a layer of anhydrous chloride of sodium 

 nearly half as thick as the mixture, and over this a layer of fluoride of 

 calcium (fluor spar) in pieces as large as a pea. This latter substance 

 is for the purpose of preventing the mixture from being projected out of 

 the crucible, a rather violent reaction being always the result. 



The crucible, thus charged and covered with a lid, is placed in a forge 

 or blast-furnace, and heated gently, and for some considerable time ; be- 

 fore the reddening of the crucible the reduction has taken place ; this is 

 indicated by a whistling noise in the interior of the mass, and a yellow 

 flame rising above the crucible ; at this point the heat is augmented, and 

 carried to a reddish white. The whole is kept at this temperature for 

 about a quarter of an hour, and left to cool by shutting up all the open- 

 ings into the furnace. On breaking the crucible the metal is found in 

 one piece at the bottom. The theoretical quantity of the metal is never 

 obtained. The analysis of the fluoride gives in the composition Mn H, 

 from this 100 parts of sodium ought to decompose 203-5 parts of the 

 fluoride of manganese to form 183'5 parts of fluoride of sodium, and to 

 furnish 120 parts of manganese. However, we ought to be contented with 

 little more than the half. 



Manganese thus prepared possesses properties essentially different from 

 those which have been commonly attributed to it. Its color is that of 

 some cast iron : it is brittle, and docs not flatten out to the hammer, or 

 to other mechanical forces ; it is very hard, and not scratched by a file ; 



